Tunable narrowband optical parametric oscillator using a transversely chirped Bragg grating

Abstract

We demonstrate a novel technique for locking and tuning of a near-degenerate nanosecond optical parametric oscillator (OPO) using a transversely chirped volume Bragg grating. When the grating was translated, the OPO signal wavelength could be tuned from 1011 to 1023 nm (3.5 THz). The OPO was based on a periodically poled KTiOPO(4) as a nonlinear crystal and was pumped at 532 nm with up to 1.9 mJ of energy. The generated signal at an energy of 0.37 mJ had a bandwidth of 0.50 nm and a suppression of broadband background of >30 dB. The demonstrated technique is widely applicable for the construction of narrowband tunable sources.

Stretching of picosecond laser pulses with uniform reflecting volume Bragg gratings

“…A certain tunability of these parameters can be realized in particular grating designs, because of the presence of transverse degrees of freedom in operation with VBGs. For example, besides the standard resonant wavelength shift with angular tuning of the reflective VBG [25], the variations in the grating parameters with parallel translation of the VBGs along the transverse coordinate have been used in [26], in order to tune the resonant wavelength, and in [27], so as to tune the transmission bandwidth of the resonant VBG cavity. The simplest approach to creating a VBG producing a tunable pulse duration is to cut a VBG with varying length from a glass wafer using a recorded standard uniform modulation pattern, as shown on the right of figure 4.…”

Cavity length resonances in a nanosecond singly resonant optical parametric oscillator

“…In addition to the main signal and idler peaks additional wavelengths seeded by four wave mixing (FWM) are generated. The FWM is a cascaded χ (2) interaction caused by second harmonic generation of the pump and idler and subsequent difference frequency generation [12,13]. Because of the wide phase matching bandwidth this parasitic interaction can reach macroscopic efficiency.…”

Single-Frequency Operation of a Near-degenerate Optical Parametric Oscillator Using a Transversally Chirped Volume Bragg Grating

“…Recently, Volume Bragg Gratings (VBGs) have emerged as very-narrow, high-efficiency spectral filters for laser applications. They have been used in OPOs to provide narrowband tunable emission [3], and single-frequency operation at a fixed wavelength off degeneracy [4]. In this work, we use a VBG to produce tunable single-frequency radiation very close to degeneracy, while benefiting from the high gain of PPLN with identical polarizations.…”