Sub-four-cycle laser pulses directly from a high-repetition-rate optical parametric chirped-pulse amplifier at 34 μm

Abstract

We generate sub-four-cycle pulses (41.6 fs) with 12 μJ of pulse energy in the mid-infrared spectral range (center wavelength 3.4 μm) from a high-repetition-rate, collinear three-stage optical parametric chirped-pulse amplifier (OPCPA) operating at 50 kHz. Apodized aperiodically poled MgO:LiNbO3 crystals with a negative chirp rate are employed as gain media to achieve ultrabroadband phase-matching while minimizing optical parametric generation. The seed pulses are obtained via a 1.56 μm femtosecond fiber laser, which is spectrally broadened in a dispersion-shifted telecom fiber to support 1000 nm bandwidth idler pulses in the mid-infrared.

Mid-infrared pulse generation via achromatic quasi-phase-matched OPCPA

“…The residual fluctuation of the spectral phase results in a pedestal in the time domain. Note that, as discussed in [18], the fluctuations in spectral phase originate from our near-IR seeding scheme, rather than any of the OPCPA devices. The reconstructed temporal intensity profile is shown in Fig.…”

“…1. Here, we use a new final power amplifier stage, while keeping the seeding and pre-amplification layout the same as the system reported in [18]. For completeness, we next give an overview of the system layout.…”

“…After the pulse chirping arrangement, there are two collinear pre-amplifiers based on apodized APPLN gratings [23], which we denote as OPA1 and OPA2. As mentioned above, the seeding, chirping, and pre-amplification components of the system are the same as described in [18].…”

“…These include work based on periodically poled lithium niobate (PPLN) [8][9][10][11][12], birefringent phase-matching (BPM) [13][14][15], and aperiodic PPLN (APPLN; also referred to as chirped QPM devices) [16][17][18]. This latter approach is attractive because it allows broadband phase-matching despite the material's dispersion and damage threshold.…”

Ultrafast Mid-IR Laser Pulses Generation via Chirp Manipulated Optical Parametric Amplification

“…Few-cycle pulses, ranging from near-infrared (NIR) to Mid-IR, have been successfully generated from QPM-OPA schemes using crystals such as PPLN, PPSLT, and PPKTP, etc. [79][80][81][82][83][84][85][86][87][88][89][90][91][92].…”