Microlaser

An apparatus for generating laser radiation in an optical spectral region comprising:

• a pair of opposed reflectors defining a high-finesse optical cavity therebetween;
• a source that delivers particles into the cavity;
• a plurality of the particles, each individual particle being excited from a lower energy level to an upper energy level and injected into the cavity, the cavity geometry being substantially matched to the energy transition between the upper level and lower level such that upon sequential entry of a plurality of particles into the cavity, the average number of particles in the cavity being equal to or less than one;
• and
• an exit aperture through which laser radiation in the optical spectral region is emitted from the cavity.

A method for measuring coherent radiation in an optical spectral region comprising the steps of:

• providing an optical cavity between a pair of reflectors;
• providing a detector that is optically coupled to an exit aperture of the optical cavity;
• providing a source of a plurality of atoms at an upper energy level;
• injecting the individual excited atoms into the cavity in sequence, such that the atoms undergo a transition in energy from the upper level to a lower level such that there is an average number of atoms in the cavity is less than one;
• and
• coupling coherent radiation in the optical spectral region from the cavity to the detector.

A method for generating coherent radiation in an optical spectral region comprising the steps of:

• providing an optical cavity between a pair of reflectors;
• exciting a plurality of particles from a lower energy level to an upper energy level with an optical pump, the optical pump having a frequency corresponding to an energy transition of the particles;
• injecting the individual excited particles into the cavity in sequence, such that the particles undergo a transition in energy from the upper level to the lower level to provide an average number of particles in the cavity that is less than one and an average number of photons in the cavity that is greater than one;
• and
• emitting coherent radiation in the optical spectral region from the cavity.