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Two-octave mid-infrared pulses via chirp-optimized cascaded intra-pulse difference frequency generation
Optics Express
|July 30, 2025
Summary
Chirp-optimized cascaded intra-pulse difference frequency generation (CC-IDFG) generates ultra-broadband mid-infrared pulses. This method overcomes crystal phase-matching limitations, enabling sub-cycle pulse generation.
Area of Science:
- Nonlinear Optics
- Ultrafast Laser Science
- Quantum Optics
Background:
- Intra-pulse difference frequency generation (IDFG) is crucial for producing carrier-envelope-phase (CEP) stable mid-infrared (MIR) pulses.
- Current IDFG methods are limited by crystal phase-matching bandwidth, restricting spectral bandwidth to approximately one octave.
Purpose of the Study:
- To overcome the phase-matching bandwidth limitation in nonlinear crystals for IDFG.
- To demonstrate a novel chirp-optimized cascaded IDFG (CC-IDFG) scheme for generating ultra-broadband MIR pulses.
Main Methods:
- Developed a chirp-optimized cascaded IDFG (CC-IDFG) scheme.
- Utilized cascaded nonlinear crystals: BBO, MgO:LiNbO3, and BIBO.
- Manipulated the chirp of a supercontinuum pulse in the 0.5-1 µm range.
Main Results:
- Generated an ultra-broadband pulse spanning 1-4 µm.
- Achieved sub-cycle MIR pulse generation, surpassing previous bandwidth limitations.
- Demonstrated the effectiveness of CC-IDFG in overcoming phase-matching constraints.
Conclusions:
- The CC-IDFG scheme offers an effective method for generating ultra-broadband pulses.
- This technique is highly beneficial for applications like arbitrary waveform tailoring, isolated attosecond pulse generation, and ultrafast electron dynamics control.
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