Photonic molecule lasing

Krishna Rai Dastidar, Lipika Adhya, Ratan Kumar Das

Che Ting Chan

Satoru Ishii, Toshihiko Baba

We demonstrate the bistable lasing in a photonic molecule consisting of twin microdisks. When the photonic molecule was nonuniformly photopumped, the bistability and/or mode switching were observed with an effective pump power of <100μW. The rate equation analysis indicated that the operation was based on saturable absorption and gain switching, which depended on the nonuniformity, disk diameter detuning, and Q factors of coupled modes. Such a bistable laser, particularly showing the mode switching, will be applied for ultrasmall high-speed optical memories, flip-flops, and so on.

Peng, Ozdemir, Jian-Rong Zhu +1 more

V. P. Klochkov, E. B. Verkhovskiĭ

The threshold pump power density for lasing in dye solutions is found to depend on the photon energy of pumping radiation. An increase in the pumping photon energy can significantly lower the threshold pump power of dye lasers. For an ethanol solution of rhodamine 6G with a concentration of 4×10 18 cm −3 , the threshold power density for pumping radiation with a wavelength of 532 nm is 20-fold higher than for pumping radiation with a wavelength of 347 nm. This phenomenon is associated with the competition of collective spontaneous emission, which can lead to the efficient deactivation of excited molecules in femtosecond times, and the dephasing of excited molecules due to the intramolecular nonradiative processes of absorbed-energy conversion. An increase in the dephasing rate with the increasing energy of exciting photons lowers the efficiency of collective spontaneous emission and increases the concentration of dephased excited molecules responsible for lasing.