High-energy, near- and mid-IR picosecond pulses generated by a fiber-MOPA-pumped optical parametric generator and amplifier

Abstract

Abstract:We report a high-energy picosecond optical parametric generator/amplifier (OPG/A) based on a MgO:PPLN crystal pumped by a fiber master-oscillator-power-amplifier (MOPA) employing direct amplification. An OPG tuning range of 1450-3615 nm is demonstrated with pulse energies as high as 2.6 μJ (signal) and 1.2 μJ (idler). When seeded with a ~100 MHz linewidth diode laser, damage-limited pulse energies of 3.1 μJ (signal) and 1.3 μJ (idler) have been achieved and the signal pulse time-bandwidth product is improved to ~2 times transformlimited. When seeded with a 0.3 nm-bandwidth filtered amplified spontaneous emission source, crystal damage is avoided and maximum pulse energies of 3.8 μJ (signal) and 1.7 μJ (idler) are obtained at an overall conversion efficiency of 45%.

Highly efficient difference-frequency generation for mid-infrared pulses by passively synchronous seeding

“…Notably, the DFG technique is featured with single-pass configuration, simple lightpath alignment and reduced number of optical components, which thus provides desirable advantages like compactness, robustness and versatility [14] . Additionally, it has been shown that simultaneous injection of signal and pump fields could significantly lower the required pump power to approach high-power and/or high-efficiency performance [15][16][17] .…”

Narrowband cw injection seeded high power femtosecond double-pass optical parametric generator at 43 MHz: Gain and noise dynamics

“…The idea behind this so-called injection seeding is [17,18] as follows: Even if the power per pump pulse injected into the system by the cw diode laser was only on the order of the vacuum noise, which is not the case, it will still stabilize the output power of the system. However, the injected radiation is not just amplified by the OPG, which would strongly limit its spectral bandwidth [18,19], but only acts as starting mechanism for the parametric generation. Thus the spectral and temporal dynamics are dominated rather by the OPG process.…”

Multi-Watt-level 3.28–3.45 µm difference frequency generation using synchronous fiber lasers

“…An alternative to OPOs is to make use of single-pass nonlinear conversion schemes, either (unseeded) optical parametric generation (OPG) or (seeded) optical parametric amplification (OPA). Typical OPA single-pass pulsed conversion schemes use a low-average power continuous-wave (CW) signal seed and a high peak-power pump source [3,4]. This approach is simple, and generally preferred to OPG, due to the broad spectral linewidths that can accompany unseeded parametric generation.…”

“…We achieve a peak converted pump power of 72%, where the total DFG power is the sum of the amplified signal and generated idler powers. This configuration has two key merits over a comparable CW seeded OPA: the use of two pulsed sources lowers the peak-power requirements on the pump source, allowing the peak pump intensity in the crystal to remain below the photorefractive damage thresholds for MgO-PPLN (typically quoted in the range 0.1-1.0 GW/cm 2 at 1.064 µm [3,4], manufacturer and crystal specific); and the pulse duration of the idler can be tuned through adjustment of the relative delay between the pump and signal pulses. Herein, we adopt the nomenclature DFG rather than OPA due to the relative powers of the pump and signal.…”