The application of high-power, few-cycle, long-wave infrared (LWIR, 8–20 µm) pulses in strong-field physics is largely unexplored due to the lack of suitable sources. However, the generation of intense pulses with >6 µm wavelength range is becoming increasingly feasible with the recent advances in high-power ultrashort lasers in the middle-infrared range that can serve as a pump for optical parametric amplifiers (OPA). Here we experimentally demonstrate the feasibility of this approach by building an OPA pumped at 2.4 µm that generates 93 µJ pulses at 9.5 µm, 1 kHz repetition rate with sub-two-cycle pulse duration, 1.6 GW peak power, and excellent beam quality. The results open a wide range of applications in attosecond physics (especially for studies of condensed phase samples), remote sensing, and biophotonics.
We present a method for increasing the power of mid-infrared laser pulses generated by a conventional beta-barium borate (BBO) optical parametric amplifier (OPA) and AgGaS2difference frequency generation (DFG) pumped by a Ti:sapphire amplifier. The method involves an additional stage of parametric amplification with a second AgGaS2crystal pumped by selected outputs of the conventional DFG stage. This method does not require additional pump power from the Ti:sapphire laser source and improves the overall photon conversion efficiency for generating mid-infrared light. It merely requires an additional AgGaS2crystal and dichroic mirrors. Following difference frequency generation, the method reuses near-infrared light (∼1.9 µm), typically discarded, to pump the additional AgGaS2stage and amplifies the mid-infrared light twofold. We demonstrate and characterize the power, spectrum, duration, and noise of the mid-IR pulses before and after the second AgGaS2stage. We observe small changes in center frequencies, bandwidth, and pulse duration for ∼150-fs pulses between 4 and 5 µm.
more » « less- NSF-PAR ID:
- 10459321
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optics Letters
- Volume:
- 48
- Issue:
- 18
- ISSN:
- 0146-9592; OPLEDP
- Format(s):
- Medium: X Size: Article No. 4797
- Size(s):
- Article No. 4797
- Sponsoring Org:
- National Science Foundation
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