Operational Characteristics of Intracavity Singly- Resonant Optical Parametric Oscillator Pumped by
Vertical External Cavity Surface-Emitting Laser
Yu. A. Morozov, M. Yu. Morozov
Russian Academy of SciencesKotelnikov Inst. of RadioEng. & Electr. (Saratov Branch) Saratov, Russia
yuri.mor@rambler.ru
V. I. Kozlovsky
Russian Academy of Sciences P.N. Lebedev Physical InstituteMoscow, Russia vikoz@sci.lebedev.ru
O. Okhotnikov
Tampere University of Technology Optoelectronics Research Centre
Tampere, Finland Oleg.Okhotnikov@tut.fi
Abstract—The operational characteristics of a novel conti- nuous-wave compact intracavity singly-resonant optical parame- tric oscillator pumped by a vertical external cavity surface- emitting laser are numerically analyzed.
Keywords—nonlinear frequency conversion; semiconductor laser; intracavity optical parametric oscillator
Continuous-wave optical parametric oscillators (OPOs) take up a distinguished niche among the variety of optical sources which may be exploited for high-resolution spectros- copy of gaseous substances in the mid- and far-infrared ranges [1]. These coherent sources are especially attractive because of ability to produce a wide wavelength tuning combined with a narrow spectrum line under room temperature operation. Its mechanism is based on energy transfer from an optical field at the highest frequency (pump) to radiation at the intermediate frequency (signal) and at the lowest frequency (idler), the energy and momentum conservation hold. Depending on how many optical fields suffer a resonance enhancement in an ap- propriate cavity, the OPOs will fall into singly-, doubly- and triply-resonant devices. Now, the singly-resonant OPOs (SROs) are only widespread design because of hop-free wave- length tuning combined with a simple scheme and usability.
However, SROs need tens-of-watt pumping lasers to over- come the threshold of parametric generation. This threshold could be reduced if an SRO is placed within a high-finesse cavity of a pumping laser. In particular, such the intracavity SRO (ICSRO) was demonstrated with a neodymium laser [2].
Unfortunately, an ICSRO pumped by a neodymium laser ap- pears to show pronounced relaxation oscillations of output intensity because laser active medium exhibits a long lifetime of excited state. D. Stothard et al. [3] have proposed pumping of an ICSRO by a semiconductor vertical external cavity sur- face-emitting laser (VECSEL) in order to prevent the relaxa- tion oscillations.
Recently, we have proposed a novel type of the conti- nuous-wave ICSRO pumped by a VECSEL [4]. One of the primary goals of the proposal was to build a fairly compact device. Unlike to the ICSRO presented in [3], we have use of the same plano-concave cavity both for the pumping laser and the signal down-converted wave. The total length of the cavity with a nonlinear crystal of quasi-phase-matched GaAs used as the SRO’s gain medium is less than 20 mm. Here we report on the numerical analysis of operational characteristics of the ICSRO. The VECSEL with a quantum-well (QW) active me- dium based on GaSb material system is supposed to generate pump radiation (p≈1.98 m) for the ICSRO. These active media are known to be homogeneously broadened and free of spatial hole-burning. Both these features in combination with a large intermode beating frequency determined by the short length cavity encourage the single-mode operation of ICSRO without frequency selective elements [5]. Our analysis shows that about 35 mW of one-direction idler power (i≈16.5 m) could be generated for 15 W of primary pump power.
This study was supported by RFBR grant No.13-02- 12070-OFI_M.
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