Browsing by Subject "Sum-frequency generation"

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Open Access
A numerical solution for nanosecond single crystal upconversion optical parametric oscillators
(2005) Yalabık Ateş
A model of single-crystal upconversion optical parametric oscillators (OPO’s) is a valuable tool for design and optimization. In these devices, a single nonlinear crystal is used both for optical parametric amplification (OPA) and sumfrequency/second-harmonic generation (SFG/SHG). This thesis presents a computational model for single-crystal upconversion OPO’s with pump pulse durations on the order of few nanoseconds. When the duration of the pump pulse is longer than the round trip time of the cavity used in the OPO, the transient nature of the problem must be taken into consideration. Besides the evolutions of the interacting light beams in time, the beam profiles and effects due to diffraction are incorporated into the model. Besides the model, incorporating nonlinear interaction and diffraction inside the crystal, solutions for different cavity components are given in detail. Computational results for a class-D sum-frequency OPO are presented, which are in good agreement with experimental measurements.
Open Access
Plane-wave dynamics of optical parametric oscillation with simultaneous sum-frequency generation
(Institute of Electrical and Electronics Engineers, 1999-06) Dikmelik, Y.; Akgün, G.; Aytür, O.
This paper presents a theoretical analysis of sum-frequency generating optical parametric oscillators where a single nonlinear crystal is used for both parametric generation and sum-frequency generation. In these devices, the parametric and sum-frequency generation processes are both phase matched for the same direction of propagation inside the crystal. Different polarization geometries for which this simultaneous phase-matching condition can potentially be satisfied are identified and categorized, for both birefringent and quasi-phase-matching methods. Plane-wave coupled-mode equations are presented for each of these categories. Solutions of these coupled mode equations and calculation of the single-pass saturated signal gain are outlined. Intracavity signal photon flux density calculations based on these solutions lead to stable steady-state upconversion, multistability, and chaos. The dependence of the photon conversion efficiency on various design parameters are investigated.
Open Access
Plane-wave theory of single-crystal upconversion optical parametric oscillators
(1998) Dikmelik, Yamaç
'rhis thesis pi'('s('nts a theoi'etical analysis of single-crystal upconversion optical parametric oscillators (OPO’s) where a single nonlinear crystal is used for both the OPO and sum-frequency generation (SPG) or second-harmonic generation (SHG). In these devices, the OPO and SFG/SHG processes are both phase matched for the same direction of propagation inside the crystal. Different polarization geometries for which this simultaneous phase matching condition can potentially be satisfied are identified and categorized, for both biréfringent. a.nd quasi-phcise matching methods. This categorization results in four classes of sumfrequency generating OPO’s (SF-OPO’s) and three classes of self-doubling OPO’s (SD-OPO’s). Plane-wa.ve coupled mode equations a.re presented for each of these seven classes. Solutions of these coupled mode equations, and calculation of the single-pass saturated signal gain are outlined. The dependence of the photon conversion efficiency on various design parameters are investigated. .Λ pulsed plane-wave model that takes into account the temporal profiles of the fields and the group velocity mismatch between pulses is constructed. This model is in good qualitative agreement with experimental measurements of a class-G SF-OPO.
Open Access
Simultaneous optical parametric oscillation and sum-frequency generation within a single crystal for converting 1064 nm into 627 nm
(IEEE, 2005-07) Figen, Z. Gürkan; Aytür, Orhan
We report a 1064-nm pumped optical parametric oscillator based on a single KTiOAsO4 crystal that simultaneously generates the sum frequency of the pump and signal wavelengths, providing a 627 nm output with a high conversion efficiency.
Open Access
Single-crystal sum-frequency-generating optical parametric oscillator
(Optical Society of America, 1999-09) Köprülü, K. G.; Kartaloğlu, T.; Dikmelik, Y.; Aytür, O.
We report a synchronously pumped optical parametric oscillator that generates the sum frequency of the pump and the signal wavelengths. A single KTiOPO4 (KTP) crystal is used for both parametric generation and sum-frequency generation in which these two processes are simultaneously phase matched for the same direction of propagation. The parametric oscillator, pumped by a femtosecond Ti:sapphire laser at a wavelength of 827 nm, generates a blue output beam at 487 nm with 43% power-conversion efficiency. The polarization geometry of simultaneous phase matching requires rotation of the pump polarization before the cavity. Adjusting the group delay between the two orthogonally polarized pump components to compensate for the group-velocity mismatch in the KTP crystal increases the photon-conversion efficiency more than threefold. Angle tuning in conjunction with pump wavelength tuning provides output tunability in the 484–512-nm range. A plane-wave model that takes group-velocity mismatch into account is in good agreement with our experimental results.