Exhibit 4.4




THIS SECURITY HAS NOT BEEN  REGISTERED  UNDER THE  SECURITIES  ACT OF 1933, AS
AMENDED,  OR ANY STATE SECURITIES LAWS, AND MAY NOT BE OFFERED OR SOLD, UNLESS
IT HAS BEEN REGISTERED  UNDER SUCH ACT OR APPLICABLE  STATE SECURITIES LAWS OR
UNLESS AN EXEMPTION FROM REGISTRATION IS AVAILABLE.

                             PSC ACQUISITION INC.

                   SUBORDINATED INSTALLMENT PROMISSORY NOTE


US $5,000,000
                                                                 July 12, 1996

     For value received and intending to be legally bound, PSC ACQUISITION INC.,
a Delaware corporation (the "Operating Company"),  hereby promises to pay to the
order of  Spectra-Physics,  Inc.,  a  Delaware  corporation  (together  with any
subsequent holder of this Note, the "Holder"), the principal sum of Five Million
Dollars  ($5,000,000),  together with interest thereon as hereinafter  provided,
payable  at the times and in the  manner  hereinafter  provided,  and  Operating
Company further agrees as is hereinafter set forth.  Certain  capitalized  terms
used herein and not otherwise defined herein are defined in Section 12 hereof.


     1.  Interest.  This Note shall bear  interest  from the date  hereof on the
unpaid principal amount hereof at a variable rate of interest per annum equal to
the Prime Rate,  plus one percent  (1%).  This Note shall also bear  interest on
overdue  principal and, to the extent  permitted by law, on any overdue interest
at a variable  rate of interest  per annum  equal to the Prime Rate,  plus three
percent (3%). In no event shall the amount  payable by the Operating  Company as
interest on this Note exceed the highest lawful rate  permissible  under any law
applicable  thereto.  All interest shall be calculated based upon a 360 day year
and the actual  number of days  elapsed.  The  interest  rate on this Note shall
change  automatically  without notice to the Operating Company  immediately with
each change in the Prime Rate.

     2.  Payments.  The  principal  hereof  shall be  payable  in  sixteen  (16)
consecutive  quarterly  installments,  due on each April 12, July 12, October 12
and January 12, commencing October 12, 1997, each in the amount of Three Hundred
and Twelve  Thousand  Five Hundred  Dollars  ($312,500).  This Note shall have a
final maturity,  at which all principal amounts  remaining  outstanding shall be
repaid in full, on July 12, 2001.  Accrued but unpaid  interest shall be due and
payable on each  April 12,  July 12,  October  12, and  January  12,  commencing
October 12, 1996, and at maturity;  provided that interest on overdue  principal
and overdue  interest shall, at the option of the Holder,  be payable on demand.
Payments of principal  and interest  shall be made in lawful money of the United
States of  America,  by wire  transfer  of  immediately  available  funds to the
following account:

            CoreStates Bank of Delaware N.A.
            ABA:  #031000011

                     Credit:  CoreStates Bank of Delaware
                                    Demand Checking

                    Name of:  Spectra-Physics, Inc.

            Account Number:   #0095-6176

or by such other  method or to such  address  as the  Holder may  specify to the
Operating Company in writing.

     3.  Prepayment.  The  Operating  Company shall have the right to prepay the
unpaid principal balance hereof, in whole or in part, at any time so long as all
accrued  and unpaid  interest  hereunder  is  simultaneously  paid in full.  Any
partial  prepayment  of this Note pursuant to this Section 3 shall be applied to
the  payment  of  installments  of the  principal  hereof  in  inverse  order of
maturity.

     4.  Financial  Statements  And  Information.  So long as this Note  remains
outstanding,  the  Operating  Company  shall provide to the Holder the documents
described in Sections 7(a) through 7(j) of the Securities  Purchase  Agreements;
provided,  however,  that for purposes of applying this Section of this Note (i)
the  capitalized  terms  used  in  such  Sections  of  the  Securities  Purchase
Agreements  shall be deemed to have the meanings  ascribed to them in this Note,
(ii) the  phrase  "Required  Holders of the Notes and of the  Warrants"  used in
Section  7(b) of the  Securities  Purchase  Agreements  shall  mean the  Holder,
(iii) the phrase "this Agreement,  the Other Securities  Purchase Agreements and
the  Securities"  shall mean the Operative  Documents,  and (iv) the phrase "the
Seller  or"  the  phrase  "Seller  Notes  and/or  the"  in  Section  7(i) of the
Securities Purchase Agreements shall be deemed deleted.

     5.  Inspection.  The Operating  Company and the Holding Company will permit
any Person  designated by the Holder,  on reasonable  notice and at the Holder's
expense  (unless  a Default  or Event of  Default  shall  have  occurred  and be
continuing,  in which case at the  Operating  Company's  expense),  to visit and
inspect any of the properties of the Holding  Company and its  Subsidiaries,  to
examine  its and their books and  records  (and to make copies  thereof and take
extracts therefrom) and to discuss its and their affairs,  finances and accounts
with and to be  advised as to the same by, its and their  officers  and  outside
counsel  (and if a  Default  or Event of  Default  shall  have  occurred  and be
continuing,  its and their independent  accountants,  each of whom the Companies
hereby  direct  and  authorize  to  engage  in  such   discussions   under  such
circumstances),  all at such  reasonable  times and  intervals as the Holder may
desire.



     6.  Subordination  Of Notes. The provisions of Section 10 of the Securities
Purchase Agreement (other than  Section 10.4(d))  are incorporated  herein as if
set forth in full herein, provided, however, that (i) the capitalized terms used
in such Section 10 of the Securities Purchase Agreements shall be deemed to have
the  meanings  ascribed  to them in this  Note,  (ii) the  references  to  "this
Agreement" and/or "the other Securities Purchase Agreements" in Sections 10.2(a)
and  10.11  of the  Securities  Purchase  Agreements  shall be  deemed  deleted,
(iii) the  term  "Agreement"  in  Sections  10.4(a)(ii),  10.8 and  10.10 of the
Securities  Purchase  Agreements  shall mean this Note, (iv) the phrase "and the
right to  exercise  any of the  Warrants"  in  Section  10.11 of the  Securities
Purchase Agreements shall be deemed deleted, (v) in each instance where there is
a  reference  to the  vote,  consent  or  approval  of  holders  of a  specified
percentage  of the principal  amount of Superior  Indebtedness,  such  reference
shall  be  deemed  to mean  the  holders  of such  specified  percentage  of the
principal amount of each class of Superior  Indebtedness (and for this purpose a
"class" of Superior  Indebtedness  shall  refer to each of (a) the  Indebtedness
under the  Subordinated  Debt Documents and any Refinancing  Agreement  relating
thereto,  and (b) the  Indebtedness  under  the Bank  Credit  Documents  and any
Refinancing  Agreement relating thereto, each of which is a separate class,) and
(vi) Section 10.4(a)(i) shall be deemed to read:

     (i) a Material Default shall have occurred which (other than in the case of
a default  under  section  6.01(f)  of the Bank  Credit  Agreement  or  sections
16.1(e), (f) or (g) of the Securities Purchase Agreements) permits the holder or
holders of any Superior  Indebtedness  to  immediately  accelerate  the maturity
thereof;

     7.  Covenants.  Each  of the  Operating  Company  and the  Holding  Company
covenants  and  agrees  that  so  long  as any  portion  of  this  Note  remains
outstanding,  unless the Holder otherwise agrees in writing, it shall, and shall
cause its Subsidiaries to:

     7.1 Comply with each of the  covenants  set forth in Sections  14.1 through
14.19,  excluding  Section 14.6(b) and Section 14.7, of the Securities  Purchase
Agreements, provided, however, that:

     (i) the capitalized terms used in such Sections of the Securities  Purchase
Agreements shall be deemed to have the meanings ascribed to them in this Note;

     (ii) with respect to Section 14.5(a), (1) the term "Refinancing  Agreement"
as  used  in  paragraph (iv)  shall  have  the  meaning  ascribed  to it in  the
Securities Purchase Agreements,  and (2) paragraph  (ii) thereof shall be deemed
to read as follows:

     (ii)  Funded  Debt  evidenced  by the notes  issued  under  the  Securities
Purchase  Agreements and under any Refinancing  Agreement relating to such notes
(but no other  extension,  refinancing,  refunding  or  renewal  of such  Notes)
provided  that the  aggregate  principal  amount of such Funded Debt and Current
Debt  outstanding  under the Securities  Purchase  Agreements and such notes and
under  any  Refinancing  Agreement  relating  thereto  shall  at no time  exceed
$31,500,000 minus the sum of all repayments of the principal of such Funded Debt
or Current Debt.


     (iii) with respect to Section 14.16(a),  the term "the Securities" shall be
deemed replaced by the term "this Note";

     (iv) with respect to Section 14.16(c), (1) the term "Acquisition Documents"
shall be deemed  replaced by the term  "Subordinated  Debt  Documents",  (2) the
terms "any holder of any of the Securities" shall be deemed replaced by the term
"the  Holder",  (3) the terms  "Notes or to pay the Put Price under  section 12"
shall  be  deemed  replaced  by the  term  "Note",  (4) the  terms  "agreements,
documents  or  instruments  referred  to  in  section 4.3,   including,  without
limitation," shall be deemed deleted, and (5) the terms "term of the Bank" shall
be deemed replaced by the terms "term of the Subordinated Debt Documents, Bank";

     (v) with respect to Section  14.17(c),  the terms  "Agreement and the Other
Securities Purchase  Agreements" shall be deemed replaced by the term "Note" and
the terms "and thereof" shall be deemed deleted; and

     (vi) with respect to Section  14.18,  the term  "Required"  shall be deemed
deleted.

     7.2 Subject to Section 8.6 hereof,  comply with each of the  covenants  set
forth in Section 14.7 of the Securities Purchase Agreements.

     8. Remedies.

     8.1 Events Of Default Defined; Acceleration Of Maturity. If any one or more
of the following  events  ("Events of Default") shall occur (whatever the reason
for such Event of Default and whether it shall be voluntary or involuntary or be
effected by operation of law or pursuant to any judgment, decree or order of any
court or any order,  rule or regulation of any  administrative  or  governmental
body), that is to say:

     (a) if default shall be made in the due and punctual  payment of all or any
part of the  principal  of this Note when and as the same  shall  become due and
payable,  whether at the  stated  maturity  thereof,  by notice of or demand for
prepayment, or otherwise;

     (b) if  default  shall  be  made in the due  and  punctual  payment  of any
interest on this Note when and as such interest shall become due and payable and
such default shall have continued for a period of five Business Days;


     (c) if  default  shall  be made in the  performance  or  observance  of any
covenant, agreement or condition contained in Section 4 (with respect to Section
7(g) of the  Securities  Purchase  Agreements)  or  Section 5 (with  respect  to
Sections 14.2(b) or 14.5 through 14.19,  inclusive,  of the Securities  Purchase
Agreements);

     (d) if default shall be made in the  performance or observance of any other
of the covenants,  agreements or conditions contained in this Note or any of the
other Operative  Documents and such default shall have continued for a period of
30 days  after the  earlier to occur of (i) either  Company's  obtaining  actual
knowledge of such default or (ii) either Company's  receipt of written notice of
such default;

     (e) if the  Holding  Company  or any  Material  Subsidiary  of the  Holding
Company shall make a general  assignment for the benefit of creditors,  or shall
not pay its debts as they become due, or shall admit in writing its inability to
pay its  debts  as they  become  due,  or shall  file a  voluntary  petition  in
bankruptcy,  or shall be  adjudicated  bankrupt or insolvent,  or shall file any
petition  or  answer  seeking  for  itself  any   reorganization,   arrangement,
composition, readjustment,  liquidation, dissolution or similar relief under any
present or future statute, law or regulation, or shall file any answer admitting
or not contesting the material allegations of a petition filed against it in any
such proceeding,  or shall seek or consent to or acquiesce in the appointment of
any trustee, custodian,  receiver,  liquidator or fiscal agent for it or for all
or any  substantial  part of its  properties,  or  shall  (or its  directors  or
stockholders shall) take any action looking to its dissolution or liquidation;

     (f) if,  within 30 days after the  commencement  of an action  against  the
Holding  Company or any Material  Subsidiary of the Holding  Company seeking any
reorganization, arrangement, composition, readjustment, liquidation, dissolution
or similar relief under any present or future statute,  law or regulation,  such
action  shall not have been  dismissed or all orders or  proceedings  thereunder
affecting the operations or the business of the Holding Company or such Material
Subsidiary  stayed,  or if the  stay  of any  such  order  or  proceeding  shall
thereafter be set aside, or if, within 30 days after the appointment without the
consent or acquiescence  of the Holding  Company or such Material  Subsidiary of
any trustee,  custodian,  receiver,  liquidator  or fiscal agent for the Holding
Company or any  Material  Subsidiary  of the  Holding  Company or for all or any
substantial part of their respective properties, such appointment shall not have
been vacated;

     (g) if, under the  provisions  of any law for the relief or aid of debtors,
any court or governmental agency of competent  jurisdiction shall assume custody
or control of the Holding  Company or of any Material  Subsidiary of the Holding
Company or of all or any  substantial  part of their  respective  properties and
such custody or control  shall not be  terminated  or stayed within 30 days from
the date of assumption of such custody or control;


     (h) if (1) the Holding  Company or any  Subsidiary  of the Holding  Company
shall fail to (i) make any payment due on any Indebtedness (other than this Note
and other than  Indebtedness  under the Bank Credit  Documents or the Securities
Purchase  Agreements (or any Refinancing  Agreement  related  thereto)) or other
obligation  (including  any in  respect  of any  lease  or any  Shares  upon the
exercise  by any  Person  of any put or call  option or other  similar  right of
redemption or repurchase with regard to such Shares in accordance with the terms
of such option or right),  if the aggregate  outstanding  amount thereof (and of
any other  Indebtedness  or other  obligation as to which the Holding Company or
any  Subsidiary is in default)  exceeds  $2,000,000 or (ii) perform,  observe or
discharge any covenant,  condition or obligation in any  agreement,  document or
instrument  evidencing,  securing  or  relating  to such  Indebtedness  or other
obligation, if the effect of any such failure of the character described in this
clause (1) is to cause,  or permit  any other  Person to cause,  any  payment in
respect  thereof in an aggregate  amount of $2,000,000 or more to become due and
payable,  or (2) if any such  Indebtedness  or other  obligation or Indebtedness
under the Bank Credit  Documents or the Securities  Purchase  Agreements (or any
Refinancing Agreement related thereto) in aggregate amount of $2,000,000 or more
shall be  accelerated or shall become due and payable by its terms and shall not
be paid or extended;

     (i) if a final  judgment for the payment of money which,  together with all
other  outstanding  final judgments for the payment of money against the Holding
Company and/or any of its Subsidiaries, exceeds an aggregate of $2,000,000 shall
be rendered by a court of record against the Holding  Company or any Subsidiary,
and the  Holding  Company or such  Subsidiary  shall not  discharge  the same or
provide for its  discharge in  accordance  with its terms,  or procure a stay of
execution  thereof within 30 days from the date of entry thereof and within such
period of 30 days, or such longer period during which execution of such judgment
shall have been stayed,  move to vacate such  judgment or appeal  therefrom  and
cause the execution thereof to be stayed pending determination of such motion or
during such appeal;

     (j) if any  representation  or warranty made by or on behalf of the Holding
Company or any Subsidiary of the Holding Company in the  Acquisition  Agreement,
this  Note  or in any of the  other  Operative  Documents  or in any  agreement,
document or instrument  delivered  under or pursuant to any provision  hereof or
thereof shall prove to have been materially false or incorrect on the date as of
which made;


     (k) if, at any time,  this  Note or any of the  other  Operative  Documents
shall for any reason (other than the scheduled termination thereof in accordance
with its terms) expire,  fail to be in full force and effect or be  disaffirmed,
repudiated,  cancelled,  terminated  or declared to be  unenforceable,  null and
void;

     (l) if (i) any Plan shall fail to satisfy the minimum funding  standards of
ERISA  or the  Code  for any  plan  year or part  thereof  or a  waiver  of such
standards  or extension of any  amortization  period is sought or granted  under
section  412 of the Code,  (ii) a notice of intent to  terminate  any Plan shall
have been or is reasonably  expected to be filed with the PBGC or the PBGC shall
have instituted  proceedings under section 4042 of ERISA to terminate or appoint
a trustee to administer any Plan or the PBGC shall have notified  either Company
or any ERISA Affiliate that a Plan may become a subject of any such proceedings,
(iii) the aggregate "amount of unfunded benefit liabilities" (within the meaning
of section 4001(a)(18) of ERISA) under all Plans,  determined in accordance with
Title IV of ERISA,  shall  exceed  $250,000,  (iv)  either  Company or any ERISA
Affiliate  shall have incurred or is reasonably  expected to incur any liability
pursuant  to Title I or IV of ERISA or the penalty or excise tax  provisions  of
the Code relating to employee  benefit  plans,  (v) either  Company or any ERISA
Affiliate  withdraws from any Multiemployer  Plan, or (vi) either Company or any
Subsidiary of either Company  establishes or amends any employee welfare benefit
plan that  provides  post-employment  welfare  benefits  in a manner  that would
increase the liability of either  Company or any  Subsidiary  of either  Company
thereunder;  and any such event or events  described in clauses (i) through (vi)
above,  either individually or together with any other such event or events, has
resulted  in, or could  reasonably  be expected to result in a Material  Adverse
Change; or

     (m) if (i) any Person or two or more Persons  acting in concert  shall have
acquired  beneficial  ownership  (within  the  meaning  of  Rule  13d-3  of  the
Commission under the Exchange Act),  directly or indirectly,  of Voting Stock of
the Holding  Company (or other  securities  convertible  into such Voting Stock)
representing 30% or more of the combined voting power of all Voting Stock of the
Holding  Company;  (ii)  during  any  period  of up to  24  consecutive  months,
commencing  before  or  after  the  date of this  Note,  individuals  who at the
beginning of such 24-month  period were  directors of the Holding  Company shall
cease for any reason to  constitute  a majority of the board of directors of the
Holding  Company;  or (iii) any Person or two or more Persons  acting in concert
shall have  acquired by  contract or  otherwise,  or shall have  entered  into a
contract or arrangement  that,  upon  consummation,  will result in its or their
acquisition  of the power to exercise,  directly or  indirectly,  a  controlling
influence over the management or policies of the Holding Company;

then,  in the  case  of an  Event  of  Default  of the  character  described  in
subdivisions  (a), (b), (c), (d), (h), (i), (j), (k), (l) or (m) of this Section
8.1  and at the  option  of the  Holder,  exercised  by  written  notice  to the
Operating  Company,  the principal of this Note shall  forthwith  become due and
payable,  together with interest accrued thereon,  without presentment,  demand,



protest or other notice of any kind, all of which are hereby  expressly  waived,
and the Operating  Company shall forthwith upon any such acceleration pay to the
Holder the entire  principal  of and  interest  accrued on this Note,  provided,
further,  that in the case of an Event of Default of the character  described in
Subsections  (e), (f) or (g) of this  Section  8.1,  the  principal of this Note
shall forthwith  become due and payable,  together with interest accrued thereon
(including  any  interest  accruing  after  the  commencement  of any  action or
proceeding under the federal  bankruptcy laws, as now or hereafter  constituted,
or any  other  applicable  domestic  or  foreign  federal  or state  bankruptcy,
insolvency or other similar law, and any other  interest that would have accrued
but for the commencement of such proceeding, whether or not any such interest is
allowed  as an  enforceable  claim  in such  proceeding),  without  presentment,
demand,  protest or other notice of any kind, all of which are hereby  expressly
waived, and the Operating Company shall forthwith upon any such acceleration pay
to the Holder the entire principal of and interest accrued on this Note.

     8.2 Suits for Enforcement,  etc. Subject to the provisions of Section 6, in
case any one or more of the Events of  Default  specified  in Section  8.1 shall
have  occurred,  and  irrespective  of whether  this Note has become or has been
declared  immediately due and payable under Section  8.1, the Holder may proceed
to protect and enforce its rights  either by suit in equity or by action at law,
or  both.  Without  limiting  the  generality  of  the  foregoing  (and  without
derogating  from  any  provision  contained  in this  Note  or any of the  other
Operative Documents), upon the occurrence and during the continuance of an Event
of  Default,  the  Holder  shall have the right to apply for and have a receiver
appointed for each of the Companies and their  respective  Subsidiaries,  or any
one or more of them, by a court of competent jurisdiction in any action taken by
Holder  to  enforce  its  rights  and  remedies  hereunder  and  under the other
Operative  Documents in order to manage,  protect and preserve the assets of the
Companies and their  respective  Subsidiaries  and continue the operation of the
business  of the  Companies  and their  respective  Subsidiaries,  or to sell or
dispose of the assets of the Companies and their respective Subsidiaries, and to
collect all  revenues  and profits  thereof and apply the same to the payment of
all expenses and other charges of such receivership,  including the compensation
of the receiver,  and the Companies hereby consent to such  appointment  without
regard to the existence of any misfeasance or malfeasance or the presence of any
defenses that would otherwise be available to such application.


     8.3 Remedies Cumulative.  No remedy conferred in this Note or in any of the
other  Operative  Documents  upon the Holder is intended to be  exclusive of any
other remedy, and each and every such remedy shall be cumulative and shall be in
addition to every other remedy given hereunder or thereunder or now or hereafter
existing at law or in equity or by statute or otherwise.

     8.4 Remedies Not Waived.  No course of dealing  between  either Company and
any of their respective  Subsidiaries,  on the one hand, and the Holder,  on the
other hand,  and no delay by the Holder in  exercising  any rights  hereunder or
under any of the other  Operative  Documents  shall  operate  as a waiver of any
rights of any such holder.


     8.5  Application  of  Payments.  In case any one or more of the  Events  of
Default specified in Section 8.1 shall have occurred,  all amounts to be applied
to the prepayment or payment of the Note, shall be applied, after the payment of
all  related  costs and  expenses  incurred  by the Holder  (including,  without
limitation,  reasonable  compensation  to any  and  all  trustees,  liquidators,
receivers or similar  officials and reasonable fees,  expenses and disbursements
of counsel) in such order of priority as is determined by the Holder.

     8.6 Automatic Waivers of Certain Financial  Covenant  Defaults.  If default
shall be made in the  performance  or observance  of the covenants  contained in
Section 7.2  hereof,  and the  Required  Holders of the notes  issued  under the
Securities  Purchase  Agreements  waive,  in  accordance  with the  terms of the
Securities  Purchase  Agreements,  the  analogous  default  under the  analogous
provisions  of  Section  14.7  of  the  Securities  Purchase  Agreements,  then,
notwithstanding  any other provision  herein to the contrary,  upon receipt of a
copy of such waiver, the Holder shall be deemed to have also waived such default
under Section 7.2 hereof,  on the same terms and subject to the same  conditions
as the analogous  default was waived under the Securities  Purchase  Agreements;
provided that in the event the Holding Company or any of its  Subsidiaries  pays
the  holders of the notes  under the  Securities  Purchase  Agreements  a fee or
increases  the rate of interest to be paid to such  Holders in  connection  with
obtaining such waiver, the Operating Company shall at the same time pay Holder a
proportional  fee or  shall  make  adjustments  to  the  interest  rate  payable
hereunder to reflect comparable treatment of Holder hereunder.

     9. Expenses;  Indemnity. The Companies,  jointly and severally, will pay or
cause to be paid (or reimbursed,  as the case may be) and will defend, indemnify
and hold the  Holder and each of its  directors,  officers,  employees,  agents,
advisors and Affiliates (each, an "Indemnitee") harmless (on an after tax basis)
in respect of all costs, losses,  expenses (including,  without limitation,  the
reasonable  fees,  costs,  expenses  and  disbursements  of counsel) and damages
(collectively,   "Indemnified  Costs")  incurred  by  or  asserted  against  any
Indemnitee in connection with the performance and/or enforcement of this Note or
any of the other Operative Documents (including,  without limitation,  so-called
work-outs  and/or  restructurings  and  all  amendments,  waivers  and  consents
hereunder  and  thereunder,  whether or not  effected)  which may  otherwise  be
related  in any  way to this  Note  or any  other  Operative  Documents  or such
Indemnitee's   relationship  to  either  Company  or  any  of  their  respective
Affiliates or any of their respective properties and assets, including,  without
limitation, any and all Indemnified Costs related in any way to the requirements
of any Environmental Laws (as the same may be amended,  modified or supplemented
from  time to  time) or to any  environmental  investigation,  assessment,  site
monitoring,  containment, clean up, remediation, removal, restoration, reporting
and  sampling,  whether or not  consented  to, or  requested or approved by, any
Indemnitee, and whether or not such Indemnified Cost is attributable to an event
or condition  originating from any properties or assets of either Company or any
of their respective Subsidiaries or any other properties previously or hereafter
owned, leased, occupied or operated by either Company or any of their respective
Subsidiaries.  Notwithstanding  the foregoing,  the Companies shall not have any
obligation to an Indemnitee under this Section 9 with respect to any Indemnified
Cost which is finally  determined by a court of competent  jurisdiction  to have
arisen solely and directly as a result of the willful misconduct or bad faith of
such Indemnitee.


     10.  Governing  Law;  Jurisdiction;  Waiver of Jury  Trial.  This Note and,
unless  explicitly  provided  otherwise  therein,  each of the  other  Operative
Documents,  including  the  validity  hereof  and  thereof  and the  rights  and
obligations  of the parties  hereunder and  thereunder,  and all  amendments and
supplements  hereof and  thereof  and all waivers  and  consents  hereunder  and
thereunder,  shall be construed in accordance  with and governed by the domestic
substantive laws of the State of New York without giving effect to any choice of
law or conflicts of law  provision or rule that would cause the  application  of
the domestic substantive laws of any other jurisdiction.  The Operating Company,
to the extent that it may lawfully do so, hereby consents to service of process,
and to be sued, in the State of New York and consents to the jurisdiction of the
courts of the State of New York and of the United States District Courts for the
Southern  District of New York, as well as to the  jurisdiction of all courts to
which an appeal  may be taken  from such  courts,  for the  purpose of any suit,
action or other  proceeding  arising out of any of its obligations  hereunder or
thereunder or with respect to the transactions  contemplated  hereby or thereby,
and expressly  waives any and all objections it may have as to venue in any such
courts.  The  Operating  Company  further  agrees that a summons  and  complaint
commencing  an action or  proceeding  in any of such  courts  shall be  properly
served  and  shall  confer  personal  jurisdiction  if served  personally  or by
certified  mail to it at its  address  set  forth in  Section 11.6  hereof or as
otherwise provided under the laws of the State of New York.  Notwithstanding the
foregoing,  each Company agrees that nothing  contained in this Section 10 shall
preclude the  institution  of any such suit,  action or other  proceeding in any
jurisdiction other than the State of New York. THE OPERATING COMPANY IRREVOCABLY
WAIVES  ALL  RIGHT TO A TRIAL BY JURY IN ANY SUIT,  ACTION  OR OTHER  PROCEEDING
INSTITUTED BY OR AGAINST SUCH COMPANY IN RESPECT OF ITS OBLIGATIONS HEREUNDER OR
THEREUNDER OR THE TRANSACTIONS CONTEMPLATED HEREBY OR THEREBY.

     11. General Provisions.

     11.1 This Note (together with the other Operative  Documents)  embodies the
entire  agreement  and  understanding  among the  Holder and the  Companies  and
supersedes  all prior  agreements  and  understandings  relating  to the subject
matter hereof.

     11.2 Each  covenant  contained  herein  and in each of the other  Operative
Documents  shall be construed  (absent an express  provision to the contrary) as
being independent of each other covenant  contained herein and therein,  so that
compliance  with any one  covenant  shall not (absent  such an express  contrary
provision) be deemed to excuse compliance with any other covenant.

     11.3  If any  provision  in  this  Note  or in any of the  other  Operative
Documents refers to any action taken or to be taken by an Person,  or which such
Person is prohibited from taking,  such provision  shall be applicable,  whether
such  action is taken  directly or  indirectly  by such  Person,  whether or not
expressly specified in such provision.


     11.4 The Holder shall not be required to pursue any party hereto, including
any guarantor, before exercising any other such rights.

     11.5 If any of the  terms  or  provisions  of this  Note  shall  be  deemed
unenforceable,  the  enforceability  of the remaining terms and provisions shall
not be affected.

     11.6 All communications provided for herein and, unless explicitly provided
otherwise therein,  in any of the other Operative  Documents shall be in writing
and sent (a) by telecopy if the sender on the same day sends a  confirming  copy
of such  communication  by a  recognized  overnight  delivery  service  (charges
prepaid),  (b) by a recognized overnight delivery service (charges prepaid),  or
(c) by messenger.  Any such  communication must be sent (i) if to either Company
(or any Subsidiary of either Company), to such Company (or such Subsidiary) at:

                        PSC Inc.
                        675 Basket Road
                        Webster, New York 14580
                        Telephone (716) 265-1600
                        Fax (716) 265-6402
                        Attention:  William J. Woodard,
                                      Vice-President - Finance

or at such other address (or telecopy  number) as may be furnished in writing by
the Companies, to the Holder at:

                        Spectra-Physics, Inc.
                        108 Webster Building
                        3411 Silverside Road
                        Wilmington, Delaware 19810
                        Telephone:  (302) 478-4600
                        Fax:  (302) 478-8962
                        Attention:  Ms. Barbara Schoenberg

or at such other  address  as may be  furnished  to the  Companies  in  writing.
Communications  under this Section 11.6 shall be deemed given only when actually
received.

     11.7 The section  headings of this Note are for convenience  only and shall
not affect the meaning or interpretation of this Note or any provision hereof.

     11.8 This Note  shall  inure to the  benefit of and be  enforceable  by the
respective successors and assigns of the Holder.


11.9 This Note is being  issued  pursuant to the  Acquisition  Agreement  and in
payment  of the  purchase  price  for  the US  Assets.  Pursuant  to the  Merger
Agreement,  immediately  after the issuance of this Note, the Operating  Company
will merge into Scanning and Scanning will be the surviving corporation.

     11.10 This Note is to be  guaranteed  by the  Holding  Company  and by each
Subsidiary of the Holding  Company  (other than any Foreign  Subsidiary  and the
Operating Company), including any Person which hereafter becomes a Subsidiary of
the Holding Company (other than any Foreign Subsidiary), pursuant to a guarantee
substantially  in  the  form  of  Exhibit  A  attached  hereto  (each,  a  "Note
Guarantee";  collectively, the "Note Guarantees"). The Holding Company, and each
other Person signing a Note Guaranty,  by execution  thereof,  agrees to perform
each of the provisions hereof applicable thereto.

     11.11 Any term of this  Note  and,  unless  explicitly  provided  otherwise
therein,  of any of the other  Operative  Documents may, with the consent of the
Companies,  be amended, or compliance  therewith may be waived, in writing only,
by the Holder,  provided  that no such  amendment  or waiver  shall extend to or
affect  any  obligation  not  expressly  amended  or waived or impair  any right
consequent thereon.

     12. Defined Terms.

     12.1 The term  "Acquisition  Agreement"  shall mean that certain  Asset and
Stock Purchase  Agreement  dated May 20, 1996, by and among PSC Inc., a New York
corporation, the Holder and Spectra-Physics Holding, S.A., a French corporation,
as amended, modified, and supplemented from time to time.

     12.2 The term  "Affiliate"  shall mean Affiliate as defined in Section 15.1
of the Securities  Purchase  Agreements  but shall not include  Spectra-Physics,
Inc., a Delaware corporation or any of its affiliates.

     12.3 The term "Default" shall mean any condition or event which constitutes
or, after notice or lapse of time or both, would constitute an Event of Default.

     12.4 The term "Event of Default"  shall have the meaning  ascribed to it in
Section 8 hereof.

     12.5 The term  "Material  Adverse  Change"  shall mean a  material  adverse
change in or effect  upon any of (a) the  condition  (financial  or  otherwise),
business,  performance,  operations,  properties,  profits or  prospects  of the
Operating Company individually, the Operating Company and its Subsidiaries taken
as one  enterprise,  the  Holding  Company  and its  Subsidiaries  taken  as one
enterprise  or any of the  material  assets or  liabilities  acquired or assumed
pursuant  to  the  Acquisition   Agreement,   (b)  the  legality,   validity  or
enforceability  of the Operative  Documents,  (c) the rights and remedies of the
Holder, or (d) the ability of the Holding Company,  the Operating Company or any
of the other Material  Subsidiaries to perform its obligations  under any of the
Operative Documents and/or to comply with any of the terms thereof applicable to
it.


     12.6 The term "Material  Default" shall mean (a) any default in the payment
when due of fees or expenses that constitute  Superior  Indebtedness  and/or (b)
any default  under  Section  6.01(f) of the Bank Credit  Agreement and any other
Event of Default  (other than an Event of Default under Section  6.01(a))  under
the Bank  Credit  Agreement,  or a default or Event of Default,  as  applicable,
under the analogous provisions of any Refinancing Agreement relating to the Bank
Credit  Agreement and/or (c) any default under Sections  16.1(e),  (f) or (g) of
the Securities Purchase Agreements and any other Event of Default (other than an
Event of Default under Section 16.1(a) or 16.1(b)) under the Securities Purchase
Agreements, or a default or Event of Default, as applicable, under the analogous
provisions of any  Refinancing  Agreement  relating to the  Securities  Purchase
Agreements.

     12.7 The term  "Notes" or any  reference  thereto in any  provision  hereof
which has been incorporated by reference to the Securities  Purchase  Agreements
shall mean and be deemed to refer to this Note.

     12.8 The terms  "Note  Guarantee"  and  "Note  Guarantees"  shall  have the
meanings ascribed to them in Section 11.10 hereof.

     12.9 The term  "Operating  Company"  shall  mean PSC  Acquisition  Inc.,  a
Delaware  corporation,  and any successor thereto  including,  after the Merger,
Scanning.

     12.10 The term "Operative Documents" shall mean this Note together with the
Note  Guarantees,  each as it may  from  time to time be  amended,  modified  or
supplemented.

     12.11 The term "Prime Rate" shall mean the rate  established  by CoreStates
Bank,  N.A.  ("CoreStates")  from time to time as its "base or prime  rate." The
Prime Rate is not necessarily CoreStates's most favored rate.

     12.12  The term  "Refinancing  Agreement"  shall  mean (i) the  Refinancing
Agreement as defined in the Securities  Purchase  Agreements,  and (ii) the loan
agreements,  documents and instruments, if any, entered into by the Companies in
compliance  with this Note,  pursuant to which  Indebtedness  is incurred by the
Companies  which  refinances  or refunds all or any portion of the  Indebtedness
under the Subordinated Debt Documents,  provided that all of such refinancing or
refunding  Indebtedness  is  permitted  under  Section  7 hereof  and  provided,
further,  that the terms of such loan  agreements,  documents  and  instruments,
taken as a whole,  are no more  restrictive  upon the  Obligors  and are no more
adverse to the  interests  of the Holder  than  those of the  Subordinated  Debt
Documents.


     12.13 The term "Restricted Payment" as applied to any Person shall mean:

     (a) any dividend or other distribution,  direct or indirect,  on account of
any  Shares of such  Person now or  hereafter  outstanding  (including,  without
limitation,  Preferred Shares) or any securities convertible into or exercisable
or  exchangeable  for such Shares or any rights,  options or warrants to acquire
any such Shares,  except (i) any such  dividend or  distribution  payable to the
Holding  Company,  the  Operating  Company  and/or any  Wholly-Owned  Subsidiary
Guarantor and (ii) a pro rata distribution payable to all of the stockholders of
the Holding  Company solely in shares of Common Stock of the Holding Company and
as a result of which there is no change in the  relative  ownership  interest of
any stockholder in the Holding Company or any of such stockholder's rights; and

     (b) any redemption,  retirement,  purchase or other acquisition,  direct or
indirect, of any Shares of such Person now or hereafter outstanding  (including,
without  limitation,  Preferred  Shares) or any securities  convertible  into or
exercisable or exchangeable  for such Shares or any rights,  options or warrants
to acquire any such Shares.

     12.14 The term "Securities  Purchase  Agreements"  shall mean those certain
Securities  Purchase  Agreements  dated  as of the  date  hereof  by  and  among
SpectraScan,   Inc.,  a  Delaware  corporation,  the  Holding  Company  and  the
institutional  investors  named therein with respect to the issuance and sale by
the  Operating  Company  to such  institutional  investors  of an  aggregate  of
$30,000,000  principal amount of its 11.25% Senior  Subordinated Notes due 2006,
as such Securities  Purchase  Agreements exist on the date hereof.  This Section
12.14  shall not be  interpreted  so as to restrict  the Holding  Company or its
Subsidiaries  from  entering  into any  amendment,  modification,  supplement or
waiver of the Securities Purchase  Agreements  permitted by the other provisions
hereof.

     12.15 The term  "Subordinated  Debt  Documents"  shall mean the  "Operative
Documents" as such term is defined in the Securities Purchase Agreements.

     12.16 The term "Subordinated  Indebtedness" shall mean the principal amount
of the  Indebtedness  evidenced by this Note,  together with any interest,  fee,
expense  and/or  other  amount  due  thereon or payable  with  respect  thereto,
including any such amounts payable by any guarantor of this Note.

     12.17  The  term  "Superior  Indebtedness"  shall  mean  (i)  the  Superior
Indebtedness under the Securities  Purchase  Agreements,  and (ii) the principal
amount of all Funded Debt and Current Debt of the  Operating  Company  under the
Subordinated  Debt  Documents or any  Refinancing  Agreement  relating  thereto,
together with any interest (including Accrued Bankruptcy Interest),  premium, if
any,  fee,  expense  and/or  other  amount due thereon or payable  with  respect
thereto,  including  any  such  amounts  payable  by  any  guarantor  under  the
Subordinated Debt Documents,  provided that the aggregate principal amount shall
at no time exceed  $31,500,000  minus the sum of all repayments of the principal
of the Indebtedness under the Subordinated Debt Documents.


     12.18  Capitalized terms used herein and not otherwise defined herein shall
have the meanings ascribed to them in the Securities Purchase Agreements.

     IN WITNESS  WHEREOF,  the  Operating  Company has executed  this Note as an
instrument under seal as of the date first above written.

                                          PSC ACQUISITION INC.



                                          By:/s/ William J. Woodard
                                             Vice President, Finance