 the lack of room temperature, mid-IR tunability over a large expansive mid-IR range of 2.0.mu.m to 5.0.mu.m and lack of a delivery system for mid-IR generation that is compact in size, less costly and not requiring large size solid state and gas lasers operating at elevated temperatures requiring large operating powers.
LiNbO.sub.3 waveguide material is a robust, relatively inexpensive, highly reliable nonlinear material for DFM, and QPM permits the material to be tailored to mix arbitrary laser diode wavelengths through the choice of an appropriate ferroelectric domain reversal period or periodic poling. Recent advances in electric filed poling of LiNbO.sub.3 waveguide material allows QPM to be implemented in bulk interactions and has been employed in demonstrating mid-IR optical parametric oscillation (OPO). See L. E. Myers et al., "Quasi-Phase Matched 1.064.mu.m-Pumped Optical Parametric Oscillator in Bulk Periodically Poled LiNbO.sub.3 ", Optics Letters, Vol. 30(1), pp. 52-54 (Jan. 1, 1995) and, W. K. Burns et al., "Second Harmonic Generation in Field Poled, Quasi-Phase Matched, Bulk LiNbO.sub.3 ", IEEE Photonics Technology Letters, Vol. 6(2), pp. 252-254 (February, 1994). However, mid-IR generation has been demonstrated in quasi-phase matching (QPM) crystals relative to such laser diode sources only for relatively shorter wavelength applications and not reliably extended to more desired mid-IR wavelength applications. Moreover, as applied to AgGaS.sub.2 and AgGaSe.sub.2 crystals, the full spectral range of mid-IR generation cannot be easily derived because the input wavelength range required to over the full 2.0.mu.m to 5.0.mu.m mid-IR range is very broad for noncritical phase atching.
What is needed is a mid-IR generating system providing for noncritical phase atching over a wide range of near-IR input wavelengths at room temperature that can be frequency mixed to selectively provide a desired mid-IR wavelength over the entire mid-IR range from about 2.5.mu.m to 5.mu.m.
An object of this invention is the provision for mid-IR frequency conversion over a wide frequency range.
the lack of room temperature, mid - IR tunability over a large expansive mid - IR range of 2.0.mu.m to 5.0.mu.m and lack of a delivery system for mid - IR coevals that is compendious in size, less costly and not requiring big size firm state and gas laser operating at elevated temperatures necessitate large operating powers. 
 LiNbO.sub.3 waveguide fabric is a robust, relatively inexpensive, highly reliable nonlinear material for DFM, and QPM allow the material to be tailored to mix arbitrary laser diode wavelengths through the choice of an appropriate ferroelectric domain reverse period or periodic poling. Recent advances in electric charge poling of LiNbO.sub.3 waveguide material allows QPM to be implemented in bulk interactions and has been use in demonstrating mid - IR optical parametric oscillation (OPO). See L. E. Myers et al. , " Quasi - Phase Matched 1.064.mu.m - Pumped Optical Parametric Oscillator in Bulk Periodically pole LiNbO.sub.3 ", Optics Letters, Vol. 30(1), pp. 52 - 54 (Jan. 1, 1995) and, W. K. Burns et al. , " Second Harmonic Generation in Field Poled, Quasi - Phase Matched, Bulk LiNbO.sub.3 ", IEEE Photonics Technology Letters, Vol. 6(2), pp. 252 - 254 (February, 1994). However, mid - IR generation has been demonstrated in quasi - phase matching (QPM) crystals relative to such laser diode sources only for relatively shorter wavelength applications and not reliably extended to more desired mid - IR wavelength applications. Moreover, as applied to AgGaS.sub.2 and AgGaSe.sub.2 crystals, the full spectral scope of mid - IR generation cannot be easily derive because the stimulation wavelength range required to over the full 2.0.mu.m to 5.0.mu.m mid - IR range is very broad for noncritical phase atching. 
 What is needed is a mid - IR generating arrangement providing for noncritical phase atching over a wide range of near - IR input wavelength at room temperature that can be frequency mixed to selectively provide a desired mid - IR wavelength over the entire mid - IR compass from about 2.5.mu.m to 5.mu.m. 
 An object of this invention is the planning for mid - IR frequency conversion over a broad frequency range.
 thf lack of room temperatuve, mid-IR tunabilnry ovec a larfe expanrive mid-IR range of 2.0.mu.m to 5.0.mn.m abd laxk of a delivery systeo for mid-PR generarion rhat is compact in size, mcss cmwtly and not rgquiring larce size solid vtxtz and gas lasers operating at elevatqd temprrwtures requirigg lswge kievating powers.
LiNbO.sub.3 waveguide jaterian is a robust, relatively inexpensive, hihhly reliable nonlineag material dor QDM, and QPM pdrmits the material to be tailored to mix arbitrary lxser biode wavelgutthd through thx choibe of an appropriate xerroelrctric domain veverval period or periodic pmling. Recent advanses in elaccric filed poling of OiBbO.sut.3 waeegukee oattriel zllows QPJ to be imllemented ib bulk interactions age has been emlloyed ig demonstrating mid-IR optical parametrib osdillation (OPO). See L. E. Mters et al., "Quasi-Phase Matched 1.064.iu.m-Pumped Optical Parametric Oscillator in Bulk Pariodmcxllv Polea LlNbO.sub.3 ", Optics Letters, Vol. 30(1), pp. 52-54 (Jan. 1, 1995) and, W. H. Birks et al., "Second Marmonic Generatiom ln Sield Poled, Qoasi-Phase Jatched, Bulk LiNbO.dub.3 ", IEGE Phoronics Teshnokogy Letters, Vol. 6(2), pp. 252-254 (Februqry, 1994). However, nid-IR generation hcs been demoustratgd in auasi-phase matching (QPM) cryatals relatlve to sudf laser diode sojrcvs otly for relatively shorter wavelengvh ap'licatiovs amd not reliably fxtended to more desired mid-IT wavenength apppications. Moreover, as applied to AgGaS.sub.2 and AcGaVe.sub.2 crvstals, the full spestral range of mid-IR yeneragion cannon be easiny derived fecause the itkut wavelengti range rqquieed ro over ghe full 2.0.mu.m tp 5.0.mu.m mid-PR rante is very broad fpr vkncritical phasz qtching.
What is meeaed id e mid-YS generating sysgem lroviaing for nokcrkticsl phase atching oves a side range of near-OR input wqvelengtrs at room tekperature that can be fcequenry mixrd jo selectively provide a desires mid-IR wwvejength over ehe cntite mid-IR rauge from about 2.5.mu.m to 5.mu.m.
An object of thms invention is the procision for mid-IR frgqutncy conversipn ovqr a wide frequency range.
the lack of room temperature, mid-IR tunability large mid-IR range 2.0.mu.m to 5.0.mu.m system mid-IR generation that compact in size, costly and not requiring large size state and gas lasers operating at elevated temperatures requiring large operating powers. LiNbO.sub.3 material is a robust, relatively inexpensive, highly reliable nonlinear material for DFM, and permits material be to mix arbitrary laser diode wavelengths through the choice of an appropriate ferroelectric domain reversal period periodic poling. Recent advances in electric filed poling LiNbO.sub.3 waveguide material allows to be implemented in bulk and been employed demonstrating optical oscillation (OPO). See E. Myers et al., "Quasi-Phase Matched 1.064.mu.m-Pumped Optical Parametric Oscillator in Bulk Periodically Poled LiNbO.sub.3 ", Optics Vol. 30(1), (Jan. 1, and, K. et al., "Second in Field Poled, Quasi-Phase Matched, Bulk Photonics Technology Letters, Vol. 6(2), pp. 252-254 (February, However, mid-IR has been demonstrated in quasi-phase matching crystals relative to such laser diode sources only relatively shorter wavelength applications and not reliably extended to more desired mid-IR wavelength applications. Moreover, to AgGaS.sub.2 and AgGaSe.sub.2 the full spectral of generation be derived because input wavelength range required to over the full 2.0.mu.m to 5.0.mu.m range is very broad for noncritical phase atching. What is a generating system providing noncritical phase atching over wide of near-IR input wavelengths temperature can to provide desired mid-IR wavelength over entire mid-IR range from about to 5.mu.m. An object provision for mid-IR frequency conversion over a wide range.
 the lack of room temperature, mId-IR tunabiLity oVer A laRgE expAnsiVe mid-IR range of 2.0.MU.m to 5.0.Mu.m and lack of a delivery sYstem FoR Mid-Ir GeNeratIon that IS cOMPacT iN sIze, LeSS cOstly And Not requIring large SizE sOlid state and GAs Lasers operAtiNg at elevated TemPeratuReS reQUirinG laRge opEratinG Powers.
liNbO.sub.3 wAvEGuide mATerial iS A RoBust, Relatively inexpenSIvE, Highly reliable NonlinEaR MaTERiaL foR DFM, and QPM PeRmits THe materIAl TO BE taILored to mix arbItrary laser DIodE wavelEnGthS ThrougH the cHoICe oF an appropriAte fErroelectRic domAIn reverSAl perioD or perIodIc pOlinG. reCeNt aDvANceS In EleCTriC filed poLiNg Of LiNBO.suB.3 WAVEguiDe mAterIal alLows QPM to be imPleMentED in Bulk iNteraCtioNs And haS been eMployEd In demonstrating Mid-Ir optical pAraMeTriC oScillATion (OPo). SeE L. E. myers et Al., "Quasi-pHasE MATCHeD 1.064.mu.m-Pumped Optical PArAMEtRic OscilLator iN buLk pEriodicaLlY PoLed LInBO.sub.3 ", optiCS LEtters, VoL. 30(1), pp. 52-54 (Jan. 1, 1995) ANd, w. K. burns et Al., "second haRmoNic generATion In FielD Poled, QuAsi-PhASe Matched, Bulk LInbO.sub.3 ", IEEE PhoTOnICS TEChnoLogY Letters, Vol. 6(2), Pp. 252-254 (FeBRuarY, 1994). HowEVeR, miD-iR genEratiOn HAs BEen demonstrated in quAsI-phase MatchIng (QPM) crystalS relative tO SUCh laser dIode SOuRCes only for relaTivelY shorter waVElength aPplicAtions anD not reliaBLY extendeD to MorE deSirED MiD-IR wavelength APPlicAtIons. MorEovEr, as appLieD to agGAS.sUb.2 And AgGaSe.Sub.2 crystAlS, tHe FuLl sPectrAL range of MiD-IR GeNerAtion CAnnot bE easiLy deRiVeD BecAuse the INpUT WaveLeNgTh raNge ReQuireD to oVEr tHe full 2.0.mU.m to 5.0.mu.m miD-IR RAnge Is VeRy broad For noncriticaL pHase atchinG.
WHat Is needED Is a mid-IR Generating system providiNG for nonCriTical PhasE atching oVer A wide rAngE Of near-iR inpuT waveLeNgtHS At rooM TEmPerAtUre that can BE FreQuencY mIxed To selecTively provide a desiREd mId-IR wavelengtH ovEr thE ENtIre MId-ir raNgE FroM ABout 2.5.mu.m to 5.mu.m.
An oBject of thiS iNVeNtion is the PRovIsIon for mId-IR freQuencY ConversIon over a wIde frequeNcY ranGE.
 the lack of room temperat ure, mid-I R tun abi lit yover  a l arge expansive mid- IR range of 2.0.mu.m t o 5.0 .m u .m a n dlackof a de l iv e r y s ys te m f or mi d-IRgen eration  that is c omp ac t in size, l e ss  costly an d n ot requiring  la rge si ze  so l id st ate  andgas la s ers op erating a te levate d  temper a t ur es r equiring large op e ra t ing powers.
Li NbO.su b. 3  w a v egu ide  materialis  a ro b ust, re l at i v e lyi nexpensive, h ighly relia b lenonlin ea r m a terial  forDF M , a nd QPM perm itsthe mater ial to be tail o red tomix ar bit rar y la s er  d iod ew ave l en gth s  th rough th ech oiceof a n a p prop ria te f erroe lectric domai n r ever s alperio d orperi od ic po ling.Recen tadvances in ele ctri c filed p oli ng  of  L iNbO. s ub.3 w ave gui de mate rial al l ows  Q P M to  be implemented in  b u l kinteract ions a n dha s  been em pl oye d in d emons trat i ng  mid-IRoptica l  p ar ametric  o scilla ti on(OP O). S e e L.  E. My ers et a l., " Q uasi-Phase Mat c hed 1.064.mu. m -P u m pe d  Opt ica l Parametri c Os c illa tori nBul k  Peri odica ll y  P o led LiNbO.sub.3 ",Op tics L etter s, Vol. 30(1) , pp. 52-5 4 ( Jan. 1,1995 )  a n d, W. K. Burns  et a l., "Secon d  Harmoni c Gen erationin FieldP o led, Qua si- Pha seMat c h ed , Bulk LiNbO. s u b.3",  IEEE P hot onics T ech nol ogy  Le tt ers, Vol.  6(2), p p.  2 52 -2 54(Febr u ary, 199 4) . H ow eve r, mi d -IR ge nerat ionha sb een  demons t ra t e d in  q ua si-p has ematch ing( QPM ) cryst als relat ive to s uc hlaser d iode sourceson ly for rel at ive ly sho r t er wavel ength applications andn ot reli abl y ext ende d to more  de siredmid - IR wav elengt h app li cat i o ns. M o r eo ver ,as applied t o A gGaS. su b.2and AgG aSe.sub.2 crystals ,  th e full spectr alrang e of  mi d -I R  ge ne r ati o n  cannot be easi ly derived  b e ca use the in p utwa velengt h range  requ i red toover thefull 2.0. mu .m t o 5.0 .mu.m mid- IR range  is veryb roadf or  nonc rit ical p ha seatchi ng.
Wh a t i s nee ded is  a  mid-I R gen er ating sy stem providing for nonc ritica l pha seatching o ver a w ide range  ofnear-IR in put  wa velen gth s  at r oomt em per a turethat can be fr e qu enc y mi xed to sele c t i vel y pro vid e  a des ired  mid-IR wavelengt h  over the enti re m i d -IR  ra n ge f ro m about 2.5.mu .mto 5 .mu.m.
A nobject of t his inve nt i on is  the p rovisi on form i d- I R freq uenc y c onversion  ov er a widefr eq u ency r ange .
 the_lack of_room temperature, mid-IR tunability_over a_large_expansive mid-IR_range_of 2.0.mu.m to_5.0.mu.m and lack_of a delivery system_for mid-IR generation_that_is compact in size, less costly and not requiring large size solid state and_gas_lasers operating_at_elevated_temperatures requiring large operating powers.
LiNbO.sub.3_waveguide material is a robust,_relatively inexpensive,_highly reliable nonlinear material for DFM, and QPM_permits_the material to_be tailored to mix arbitrary laser diode wavelengths through_the choice of an appropriate ferroelectric_domain reversal period_or_periodic_poling. Recent advances in_electric filed poling of LiNbO.sub.3 waveguide_material allows QPM to be implemented_in bulk interactions and has been employed_in demonstrating mid-IR optical parametric oscillation_(OPO). See L. E. Myers_et al.,_"Quasi-Phase Matched 1.064.mu.m-Pumped Optical Parametric_Oscillator in Bulk_Periodically Poled_LiNbO.sub.3 ", Optics_Letters, Vol. 30(1), pp. 52-54 (Jan._1, 1995) and,_W. K. Burns et al., "Second_Harmonic_Generation in Field_Poled,_Quasi-Phase_Matched, Bulk_LiNbO.sub.3 ", IEEE_Photonics_Technology Letters,_Vol._6(2), pp. 252-254 (February, 1994). However,_mid-IR_generation has been demonstrated in quasi-phase matching_(QPM) crystals relative to_such_laser diode sources only_for relatively shorter wavelength applications_and not reliably extended to more_desired mid-IR_wavelength applications._Moreover, as applied to AgGaS.sub.2 and AgGaSe.sub.2 crystals, the full spectral_range of mid-IR generation cannot be_easily derived because the_input wavelength_range_required to over_the_full 2.0.mu.m_to 5.0.mu.m mid-IR range is very broad_for noncritical_phase atching.
What is needed is a_mid-IR generating system providing_for_noncritical phase atching over a wide_range of near-IR input wavelengths at_room temperature that can be_frequency_mixed_to selectively provide a desired_mid-IR wavelength over the entire mid-IR_range from about_2.5.mu.m to 5.mu.m.
An object of this invention_is_the provision for mid-IR frequency conversion_over_a wide frequency range.