Laser action from two-dimensional distributed feedback in photonic crystals

Abstract

We report an analysis of the operation of a new type of laser resonator with two-dimensional distributed feedback from a photonic crystal. The gain medium consists of a 2-(4-biphenylyl)-5(4-tert-butylphenyl)-1,3,4-oxadiazole host doped with Coumarin 490 and DCM and is deposited on lithographically patterned Si/SiO2 structures. Bragg reflections caused by the grating diminish the group velocity of photons along some directions of crystallographic symmetry to zero, and the resulting feedback gives rise to laser oscillations. Dispersion relations for photons were calculated analytically and are used to interpret the laser emission spectra.

Flat photonic bands in guided modes of textured metallic microcavities

“…[13][14][15][16][17] There is currently much interest in the application of two-dimensional microstructuring to a variety of optical systems, such as providing in-plane confinement of certain microcavity modes, 18 complete band gaps for surface modes, 19 enhanced light extraction and out-of-plane scattering of guided modes, [20][21][22] and feedback for organic microcavity lasers. 23 In this paper, surface microstructuring 24 is used to provide band gaps for the guided modes of microcavities based on metallic mirrors. Waveguide modes are recognized as being a significant source of loss in emissive microcavity devices, most notably when the emission takes place from within a material of high refractive index.…”

Bound states in the continuum

“…Researchers first observed this effect via a suppression of radiation into the normal direction in a surface-emitting distributed feedback laser with onedimensional periodicity 58,59 . This led to PhC surface emitting lasers (PCSELs) that lase through BICs with two-dimensional periodicity 214,215 , followed by the realizations of various lasing patterns 216,217 , lasing at the blue-violet wavelengths 218 , and lasing with organic molecules 221 . The suppressed radiation at the normal direction means that a PCSEL can have a low lasing threshold but also with a limited output power.…”

“…This makes them useful for many optical and photonic applications. In particular, the macroscopic size (on the centimeter scale or larger) and ease of fabrication make BICs in PhC slabs unique for large-area high-power applications such as lasers [214][215][216][217][218][219] , sensors 220,221 , and filters 222 .…”

Photonic mode dispersion of a two-dimensional distributed feedback polymer laser

“…4,5 A number of DFB lasers have been demonstrated in organic semiconductors, employing single gratings, 6 -13,19-21 crossed double gratings, 14,22 circular gratings, 15,16 and photonic crystal structures. [23][24][25] Through active control of the photonic modes it should be possible to control lasing properties such as threshold and output coupling. It is therefore important to understand the physics of how the local photonic environment modifies emission.…”