Time-reversal constraint limits unidirectional photon emission in slow-light photonic crystals

Slow light in photonic crystals

The velocity of light in vacuum, c, is approximately 3 × 108 m s–1, fast enough to make 7.5 round-the-world trips in a single second, and to move a distance of 300 mm in 1 ns. This ultrahigh speed is advantageous for efficient data transmission between two points, whether they are separated on a global scale or on a single chip; however, it also makes control of optical signals in the time doma...

Slow light in photonic crystals

The problem of slowing down light by orders of magnitude has been extensively discussed in the literature. Such a possibility can be useful in a variety of optical and microwave applications. Many qualitatively different approaches have been explored. Here we discuss how this goal can be achieved in linear dispersive media, such as photonic crystals. The existence of slowly propagating electrom...

Photonic crystals boost light emission

Enhancement of two-photon emission in photonic crystals.

We report the influence of photonic stopgaps on two-photon excited emission from highly efficient nonlinear chromophores infiltrated into high-quality photonic crystals. We have observed a sharp decrease (filter effect) in emission within the frequency range and direction of the stopgap as well as sharp enhancement of the two-photon excited emission associated with the stopgap's edge. This effe...

Electron energy loss and induced photon emission in photonic crystals

The interaction of a fast electron with a photonic crystal is investigated by solving the Maxwell equations exactly for the external field provided by the electron in the presence of the crystal. The energy loss is obtained from the retarding force exerted on the electron by the induced electric field, and the photon emission probability is calculated from the far-field Poynting vector. The fea...