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Quantum cascade lasers are made up of many thin layers of semiconductor. An injected electron makes a small energy transition as it moves from one layer to the next, emitting light on each cascade. Because the energy steps are small, quantum cascade lasers can produce long-wavelength mid-infrared or terahertz radiation.
Free-running stable optical dissipative solitons, called Nozaki–Bekki solitons, are created in a ring semiconductor laser; their spontaneous formation with tuning of laser bias eliminates the need for an external optical pump.
Multifunctional active mid-infrared ring resonators and directional couplers with quantum cascade laser cores allow electrical control of resonant frequency and quality factors, tunable filtering and frequency comb generation.
Topological bulk BICs in the vicinity of inverted photonic band edges enable an electrically pumped, compact, single-mode, and beam engineered QCL to be operated at terahertz region.
We present a high-performance integrated platform for broadband active and passive coherent photonics based on planarized THz quantum cascade lasers, featuring low losses and improved dispersion, RF and thermal properties.
The journey to realize a terahertz quantum cascade laser that operates at room temperature has taken a jump forward with news of a device that operates at –23 °C, within the reach of Peltier coolers.
Quantum cascade lasers are bright and compact semiconductor lasers that emit light in the mid- to far-infrared spectral region. The use of a closed ring cavity has now set them on the path towards ultrafast pulses.
