A. M. Yacomotti

Excitability in a semiconductor laser with saturable absorber

We show that a monolithic and compact vertical cavity laser with intracavity saturable absorber can emit short excitable pulses. These calibrated optical pulses can be excited as a response to an input perturbation whose amplitude is above a certain threshold. Subnanosecond excitable response is promising for applications to novel all-optical devices for information processing or logical gates.

All-optical bistable band-edge Bloch modes in a two-dimensional photonic crystal

We demonstrate experimentally all-optical bistable operation in an InP-based two-dimensional photonic crystal slab lying on top of a Bragg reflector. Bistability is obtained around 1550nm, using a low group velocity mode at the band edge of the photonic dispersion characteristic. The origin of the bistable regime is shown to be the fast (275ps relaxation time), electronically induced nonlinear refraction index. A low intensity threshold of 4kW∕cm2 was observed, with a contrast of 65% between the high and low reflectivity states.

Spontaneous mirror-symmetry breaking in coupled photonic-crystal nanolasers

The observation of symmetry breaking in a coupled nanolaser system could yield new types of switchable devices.

Continuous-wave operation of photonic band-edge laser near 1.55 μm on silicon wafer

We report on the continuous-wave operation of a band edge laser at room temperature near 1.55 μm in an InGaAs/InP photonic crystal. A flat dispersion band-edge photonic mode is used for surface normal operation. The photonic crystal slab is integrated onto a Silicon chip by means of Au/In bonding technology, which combines two advantages, efficient heat sinking and broad band reflectivity.

Thermo-optical dynamics in an optically pumped Photonic Crystal nano-cavity

Linear and non-linear thermo-optical dynamical regimes were investigated in a photonic crystal cavity. First, we have measured the thermal relaxation time in an InP-based nano-cavity with quantum dots in the presence of optical pumping. The experimental method presented here allows one to obtain the dynamics of temperature in a nanocavity based on reflectivity measurements of a cw probe beam coupled through an adiabatically tapered fiber. Characteristic times of 1.0+/-0.2 micros and 0.9+/-0.2 micros for the heating and the cooling processes were obtained. Finally, thermal dynamics were also investigated in a thermo-optical bistable regime. Switch-on/off times of 2 micros and 4 micros respectively were measured, which could be explained in terms of a simple non-linear dynamical representation.

Small volume excitation and enhancement of dye fluorescence on a 2D photonic crystal surface

We demonstrate an easy-to-implement scheme for fluorescence enhancement and observation volume reduction using photonic crystals (PhCs) as substrates for microscopy. By normal incidence coupling to slow 2D-PhC guided modes, a 65 fold enhancement in the excitation is achieved in the near field region (100 nm deep and 1 microm wide) of the resonant mode. Such large enhancement together with the high spatial resolution makes this device an excellent substrate for fluorescence microscopies.

Dynamics of band-edge photonic crystal lasers

Band-edge photonic crystal lasers were fabricated and their temporal characteristics were minutely analyzed using a high resolution up-conversion system. The InGaAs/InP photonic crystal laser operates at room temperature at 1.55 microm with turn on time ranging from 17ps to 30ps.

Radiation patterns from coupled photonic crystal nanocavities

We report on far field measurements on two coupled photonic crystal nanocavities. The distinct features of the antisymmetric modes (minima of intensity at zero-emission angles) allow us to demonstrate a π-phase difference between the cavity fields, a clear signature of evanescent coupling. Good agreement between experimental results and simulated radiation patterns has been found.

Optically pumped lasing from organic two-dimensional planar photonic crystal microcavity

In this letter, we report the realization and characterization of a planar two-dimensional organic photonic crystal microcavity laser. The gain medium consists of a tris(8-hydroxyquinolinato) aluminum doped with 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran and is deposited on a lithographically patterned silicon nitride two dimensional photonic crystal H2 microcavity. The experimental results show a laser emission at 662 nm with a threshold of 9.7 μJ/cm2.

Optical amplification in two-dimensional photonic crystals

Optical amplification is demonstrated in a two-dimensional photonic crystal. Amplification at 1575nm is observed in the direction normal to the plane of periodicity, by pumping the device at 810nm. A gain up to 27dB is measured with moderate pump fluence (50μJ∕cm2). Gain is shown to clamp as laser threshold is attained.