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(Color online) Coupled cavity photonic crystal laser. (a) Scanning electron micrograph of laser structure: array of single-defect cavities. Periodicity , hole radius , and thickness . (b) Lasing mode pumped at low power (, pulsed, pump laser diameter ).
(Color online) LL curves. (a) Low-temperature lasing with pulsed excitation (, repetition) shows an averaged threshold of , corresponding to peak power. (b) At room temperature, lasing threshold increases to an averaged ( peak). (c) Continuous-wave lasing at low temperature shows a very low threshold of . Pump powers are measured before the objective lens.
(Color online) Photonic crystal laser time response. (a) At low temperature (blue curve), at two times above lasing threshold. At room-temperature (green), time response follows that of the pump laser with . Inset: calculated response to a shorter, excitation pulse shows FWMH near when pumped two times above threshold; response is faster if we assume faster carrier relaxation time . (b) Illustration of pump inefficiency in pulsed operation. Pump energy is efficiently channeled into the cavity mode only during lasing (shaded area under curve, amplified here five times visibility); much of the remaining pump energy is wasted to SE and NR losses. (c) Time-resolved PL from unpatterned QW at RT. Faster response is possible through faster relaxation into the lasing level, estimated at from fitting to the rate model.
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