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We review the history of semiconductor microlasers, and provide a selective survey of emerging topics in this field covering VCSELs, VECSELs in optically and electrically-pumped formats, and a range of microcavity devices.
Laser emission into modes of a dielectric microsphere was observed from optically pumped HgTe quantum dots on its surface. Including real-time measurement of the input pump losses reveals nanowatt threshold levels for these lasers.
Photonic crystal slab nanocavities containing one layer of quantum dots have exhibited: strong coupling to a single quantum dot; tuning by condensation of xenon gas; linewidth broadening due to ensemble dot absorption; gain and lasing.
RIN characteristics in a frequency stabilized MSL were experimentally and theoretically investigated. Average RIN level of less than -150 dB/Hz as well as Modal RIN reduction of approximately 3 dB were obtained from the frequency stabilized MSL.
Time-resolved mid-infrared pump-probe measurements in a quantum cascade laser operating above threshold reveal gain recovery dynamics to be two-fold: relaxation within a stage on a sub-picosecond scale and transport between stages on a picosecond scale.
We have developed single frequency and single spatial mode laser structures with high optical power, using an aluminium free active region, which are to our knowledge the first demonstration for Cs pumping at 852 nm.
The optical and microwave spectra of 5-mm-long quantum-dot diode lasers are investigated. Comparison of observed beating lines with quantum-well lasers shows differences in the group index, linewidth, and line shape.
Pump power scaling with spot size is studied experimentally and theoretically in a 1060 nm VECSEL with a diamond heatspreader. The dependence of the efficiency and thermal roll-over on pump spot size are discussed.
We present the first low-threshold 1.55-mum grown on GaAs. The active layer was a single GaInNAsSb quantum well surrounded by strain-compensating GaNAs barriers. The room-temperature, continuous-wave, threshold current density was 579 A/cm2 and peak output power was 130 mW.
Design and simulation are presented for a high-temperature intersubband Raman laser based on GaN/AlGaN coupled quantum wells. This laser is tunable over 3.6~5.2 mum by applying an electric field at a fixed pumping wavelength of 2.7 mum.
The 1.55 mum pulsed operation of an optically-pumped GaInNAsSb vertical-cavity surface emitting laser (VCSEL) is reported. Full temperature (10-50degC) and wavelength-dependent (1540-1560 nm) laser measurements were recorded. The annealing effect on laser performance is also shown.
We investigate interaction of THz radiation with semiconductor lasers at room temperature and show that the voltage across the diode varies linearly with the injected THz power when the diode is operated just below threshold.
Room temperature, continuous-wave operation of lambda~8.2 mum quantum cascade lasers grown by MOCVD is reported. The lasers have been processed as double-channel ridge waveguides without the need for buried heterostructures.
We demonstrate tunable semiconductor lasers based on three coupled photonic crystal sections, that allows up to 18 nm tuning range with a side-mode suppression ratio greater than 35 dB.
850 nm AlGaAs-based VCSELs with sub-micron hole arrays on the top of the DBR mirror are presented. The VCSEL exhibits lower threshold current down to 0.5 mA with enhanced optical output power by surface plasmon resonance at the Ag/SiO2 interface consisting the sub-micron metal hole arrays.
We map a laserpsilas internal temperature structure for the first time, identifying separate heat sources due to contact heating and nonradiative recombination and using this technique to compare degradation mechanisms for GaAs-based and Si-based lasers.
We demonstrate an extreme chirped pulse modelocked laser, simultaneously generating near-transform-limited 3.9 ps optical pulses and 510 ps linearly chirped output. The design overcomes fundamental limitations of energy extraction and nonlinearities induced by gain dynamics.
We demonstrate infrared lasing operation for the first time of solution-processible colloidal nanocrystal quantum dots. The 1.53 mum emission wavelength of the whispering gallery mode laser was temperature insensitive up to 250 K.
2.35 mum GaSb-based diode lasers with QW compressive strains of 1.2 and 1.7% were designed and fabricated. Devices with heavily strained active region exhibit three times higher differential gain and half the threshold current.
Novel volume Bragg laser (VOBLA) with two photo-thermo-refractive volume Bragg gratings feedback is studied on the basis of 150-mum-stripe LD. High-efficient, near diffraction-limited operation at power of 1.7 W and spectral width of 250 pm are demonstrated.
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