A degenerate four-wave mixing (DFWM) squeezed light apparatus includes one or more pump beams, a probe beam, a vapor cell, a repump beam, and a detector. The one or more pump beams includes an input power of no greater than about 150 mW. The vapor cell includes an atomic vapor configured to interact with overlapped pump and probe beams to generate an amplified probe beam and a conjugate beam. The repump beam is configured to optically pump the atomic vapor to a ground state and decrease atomic decoherence of the atomic vapor. The detector is configured to measure squeezing due to quantum correlations between the amplified probe beam and the conjugate beam. The one or more pump beams, the probe beam, and the repump beam are configured to generate two-mode squeezed light by DFWM with squeezing of at least 3 dB below shot noise.

The present disclosure provides a dark cavity laser, including: a frequency stabilized laser output device configured to generate a laser light, and perform a frequency stabilized processing on the generated laser light to output it to the dark cavity laser device as a pump light of a gain medium of a dark cavity; and a dark cavity laser device including a main cavity, and a cavity of the main cavity is provided inside with a gas chamber of a gain medium of a dark cavity laser light, where the gain medium of the dark cavity laser light is alkali metal atoms; the dark cavity laser device is configured to receive the pump light, and form a polyatomic coherent stimulated radiation between transition levels of the alkali metal atoms in the gas chamber by a weak feedback of the main cavity to generate the dark cavity laser light.

In example embodiments, a radiation source uses Rydberg states to generate coherent THz radiation (e.g., in the range of 1-20 THz). The radiation source includes a pair of pump lasers (e.g., external-cavity diode lasers (ECDLs)) optically coupled (e.g., by a dichroic mirror and optical fiber) to a heated vapor cell (e.g., a vacuum chamber) holding an atomic species (e.g., rubidium (Rb)). The pump lasers optically pump the atomic species (e.g., Rb) to a predetermined Rydberg state (e.g., the nD.sub.5/2 state), which creates a population inversion between that state (e.g., the nD.sub.5/2 state) and a lower lying Rydberg state (e.g., the (n+1)P.sub.3/2 state). The emission between these two strongly dipole coupled Rydberg states generates coherent THz radiation.

A narrow-band diode pumped alkali laser (DPAL) comprising a diode emitter assembly of broad area diode lasers arranged in a stack or array to emit longitudinally at a power level in a power range of 10-1500 W through a frequency selective element assembly aligned and positioned in an external laser cavity to the diode emitter assembly. The frequency selective element assembly comprising: an optical cell containing alkali vapor positioned between a pair of crossed polarizers; a partially reflective mirror that reflects a portion of light passing through the optical cell back toward the diode emitter assembly; and magnetic field producing components that produce a magnetic field through the optical cell that creates a 90 polarization of light passing through the optical cell at a narrow-band frequency corresponding to the absorption line of alkali atom, attenuating components of the light passing through the optical cell at frequencies outside of the narrow-band frequency.

A narrow-band diode pumped alkali laser (DPAL) comprising a diode emitter assembly of broad area diode lasers arranged in a stack or array to emit longitudinally at a power level in a power range of 10-1500 W through a frequency selective element assembly aligned and positioned in an external laser cavity to the diode emitter assembly. The frequency selective element assembly comprising: an optical cell containing alkali vapor positioned between a pair of crossed polarizers; a partially reflective mirror that reflects a portion of light passing through the optical cell back toward the diode emitter assembly; and magnetic field producing components that produce a magnetic field through the optical cell that creates a 90 polarization of light passing through the optical cell at a narrow-band frequency corresponding to the absorption line of alkali atom, attenuating components of the light passing through the optical cell at frequencies outside of the narrow-band frequency.

In example embodiments, a radiation source uses Rydberg states to generate coherent THz radiation (e.g., in the range of 1-20THz). The radiation source includes a pair of pump lasers (e.g., external-cavity diode lasers (ECDLs)) optically coupled (e.g., by a dichroic mirror and optical fiber) to a heated vapor cell (e.g., a vacuum chamber) holding an atomic species (e.g., rubidium (Rb)). The pump lasers optically pump the atomic species (e.g., Rb) to a predetermined Rydberg state (e.g., the nD.sub.5/2 state), which creates a population inversion between that state (e.g., the nD.sub.5/2 state) and a lower lying Rydberg state (e.g., the (n+1)P.sub.3/2 state). The emission between these two strongly dipole coupled Rydberg states generates coherent THz radiation.

Gaseous laser systems and related techniques are disclosed. Techniques disclosed herein may be utilized, in accordance with some embodiments, in providing a gaseous laser system with a configuration that provides (A) pump illumination with distinct edge surfaces for an extended depth and (B) an output beam illumination from a resonator cavity with distinct edges in its reflectivity profile, thereby providing (C) pump beam and resonator beam illumination on a volume so that the distinct edge surfaces of its pump and resonator beam illumination are shared-edge surfaces with (D) further edge surfaces of the amplifier volume at the surfaces illuminated directly by the pump or resonator beams, as defined by optical windows and (optionally) by one or more flowing gas curtains depleted of the alkali vapor flowing along those optical windows. Techniques disclosed herein may be implemented, for example, in a diode-pumped alkali laser (DPAL) system, in accordance with some embodiments.

Gaseous laser systems and related techniques are disclosed. Techniques disclosed herein may be utilized, in accordance with some embodiments, in providing a gaseous laser system with a configuration that provides (A) pump illumination with distinct edge surfaces for an extended depth and (B) an output beam illumination from a resonator cavity with distinct edges in its reflectivity profile, thereby providing (C) pump beam and resonator beam illumination on a volume so that the distinct edge surfaces of its pump and resonator beam illumination are shared-edge surfaces with (D) further edge surfaces of the amplifier volume at the surfaces illuminated directly by the pump or resonator beams, as defined by optical windows and (optionally) by one or more flowing gas curtains depleted of the alkali vapor flowing along those optical windows. Techniques disclosed herein may be implemented, for example, in a diode-pumped alkali laser (DPAL) system, in accordance with some embodiments.

A degenerate four-wave mixing (DFWM) squeezed light apparatus includes one or more pump beams, a probe beam, a vapor cell, a repump beam, and a detector. The one or more pump beams includes an input power of no greater than about 150 mW. The vapor cell includes an atomic vapor configured to interact with overlapped pump and probe beams to generate an amplified probe beam and a conjugate beam. The repump beam is configured to optically pump the atomic vapor to a ground state and decrease atomic decoherence of the atomic vapor. The detector is configured to measure squeezing due to quantum correlations between the amplified probe beam and the conjugate beam. The one or more pump beams, the probe beam, and the repump beam are configured to generate two-mode squeezed light by DFWM with squeezing of at least 3 dB below shot noise.

A degenerate four-wave mixing (DFWM) squeezed light apparatus includes one or more pump beams, a probe beam, a vapor cell, a repump beam, and a detector. The one or more pump beams includes an input power of no greater than about 150 mW. The vapor cell includes an atomic vapor configured to interact with overlapped pump and probe beams to generate an amplified probe beam and a conjugate beam. The repump beam is configured to optically pump the atomic vapor to a ground state and decrease atomic decoherence of the atomic vapor. The detector is configured to measure squeezing due to quantum correlations between the amplified probe beam and the conjugate beam. The one or more pump beams, the probe beam, and the repump beam are configured to generate two-mode squeezed light by DFWM with squeezing of at least 3 dB below shot noise.