Abstract: A method of generating a sequence of random bits is disclosed. The method comprises steps of (a) generating a stream of photons using a laser; (b) attenuating said series of photons; (c) reflecting at least a part of said stream of photons from a reflector positioned such that at least part of said stream of photons is directed from said reflector into the cavity of said laser; (d) directing a part of said stream of photons to a detector such that a signal proportional to the intensity of the radiation falling on said detector is produced; (e) sampling the AC component of said signal at a plurality of times, thereby obtaining a sampled signal comprising a sequence of data points; (f) obtaining the nth time derivative of said sampled signal over at least a portion of said sample signal; and (g) adding the m least significant bits (LSBs) of said nth time derivative to said sequence. By this method, truly random sequences of bits can be obtained at rates of up to at least 300 GBits/s.

Abstract: This invention concerns the realization of a Coherent-Population-Trapping (CPT) atomic frequency standard by utilization of both the phase delay and the absorption of the light transmitted through an atomic vapor. The invented method enables the use of high modulation frequency and a fast lock of a low quality oscillator to the atomic hyperfine transition.

Abstract: This invention concerns the realization of a Coherent-Population-Trapping (CPT) atomic frequency standard using a laser which has feedback from an external cavity. The mode spacing of the external cavity is adjusted to equal the hyperfine transition frequency of the atomic vapor or a sub-harmonic of it. The external cavity enhances the modulation response at the required atomic transition and improves the stability of the frequency standard.

Abstract: A method of forming a microlens, comprising providing a doped glass having at least one metallic component other than copper, and locally irradiating the doped glass by a continuous wave laser beam, so as to melt a portion of the doped glass, thereby to form the microlens.

Abstract: A phase-controlled oscillator using a resonant tunneling diode (RTD), which is included in a self-oscillating biasing circuit. A biasing voltage controls the phase of the pulsating output relative to a pulsating input signal. If the output modulates a laser, the pulse position of the laser output can be varied in time. If the output modulates a microwave or other emitter have an electromagnetic frequency equal to that of the RTD biasing circuit, the electromagnetic phase of the emission is controlled, thereby allowing phase-array radars using multiple RTD biasing circuits. Also, multiple RTD biasing circuits can have self-oscillation frequencies which are rational fractions of a single master clock frequency driving all of them. The outputs then have different frequencies but are phase locked.

Abstract: Alignment apparatus including a source of coherent radiation mounted in a reference location and arranged to provide an output beam extending along a reference axis, a laser light reflector mounted at a location sought to be aligned with respect to the reference location and/or the reference axis, a laser light scatterer arranged to receive reflected laser light from the reflector and to produce a speckle pattern and a detector arranged to sense the speckle pattern produced by the laser light scatterer in response to incident reflected laser light, whereby variations in the speckle pattern indicate changes in relative orientation between the reference location and the laser light reflector.