The present invention provides a laser, including: a medium, having a ground state, an intermediate state, and an excited state in ascending order of energy; an excitation system, configured to excite electrons in the medium from the ground state to the intermediate state; and an excitation laser, configured to drive electrons in the intermediate state at different spatial positions in the medium to the ground state through a stimulated emission process with a fixed phase relationship, to generate a laser with a shorter relative wavelength. Due to the use of an excitation laser to drive electrons from the intermediate state, the photons generated by the stimulated emission have coherence, thereby forming a laser. In the present invention, an excitation system performing primary pumping combined with an excitation laser with a relatively long wavelength performing secondary pumping generate lasers with a relatively short wavelength, and the structure of the short-wavelength laser is simple, compact, and easy to be implemented. In addition, the cost of the short-wavelength laser can be reduced, and a laser with a shorter wavelength can be obtained.

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.

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.

Devices and/or methods provided herein relate to providing conversion of photons between an optical domain and a microwave domain. An electronic structure can comprise a resonator assembly comprising a microwave resonator and an optical resonator, an optical pump waveguide that transmits an optical pump input to the resonator assembly, and an optical signal waveguide, separate from the optical pump waveguide, that transmits an optical signal relative to the resonator assembly. The electronic structure further can comprise a microwave signal waveguide that transmits a microwave signal relative to the resonator assembly. The optical pump waveguide can comprise a delay portion that delays receipt of the optical pump input to the resonator assembly through the optical pump waveguide to a time after reduction of a majority of decoherence of the resonator assembly caused by scattering of a portion of the optical pump input, which portion does not enter the optical pump waveguide.

A mid-infrared cascading fiber amplifier device having a source configured to generate a first electromagnetic wave output at a first frequency, a fiber coupled to the source and a pump coupled to the fiber and configured to generate a second electromagnetic wave output at a second frequency, wherein the second frequency is higher than the first frequency and causes the fiber to undergo two or more transitions in response to stimulation by the first electromagnetic wave output at the first frequency, wherein the first transition generates the first electromagnetic wave output approximately at the first frequency and the second transition generates the first electromagnetic wave output approximately at the first frequency.

A mid-infrared cascading fiber amplifier device having a source configured to generate a first electromagnetic wave output at a first frequency, a fiber coupled to the source and a pump coupled to the fiber and configured to generate a second electromagnetic wave output at a second frequency, wherein the second frequency is higher than the first frequency and causes the fiber to undergo two or more transitions in response to stimulation by the first electromagnetic wave output at the first frequency, wherein the first transition generates the first electromagnetic wave output approximately at the first frequency and the second transition generates the first electromagnetic wave output approximately at the first frequency.

Devices and/or methods provided herein relate to providing conversion of photons between an optical domain and a microwave domain. An electronic structure can comprise a resonator assembly comprising a microwave resonator and an optical resonator, an optical pump waveguide that transmits an optical pump input to the resonator assembly, and an optical signal waveguide, separate from the optical pump waveguide, that transmits an optical signal relative to the resonator assembly. The electronic structure further can comprise a microwave signal waveguide that transmits a microwave signal relative to the resonator assembly. The optical pump waveguide can comprise a delay portion that delays receipt of the optical pump input to the resonator assembly through the optical pump waveguide to a time after reduction of a majority of decoherence of the resonator assembly caused by scattering of a portion of the optical pump input, which portion does not enter the optical pump waveguide.

A laser pumping method pumps a primary amount of energy into a laser medium to populate an intermediate level near an upper laser level. A lesser amount of energy is pumped into the laser medium to populate an excited level that lies above the upper laser level and transfers atomic or molecular population to the upper laser level by a nonradiative process. A laser device includes a laser medium supporting four levels, including a lower laser level, an upper laser level, an excited level above the laser level from which population transfers to the upper laser level via nonradiative transition, and an intermediate level within a few kT of the upper laser level.

High power lasers and high power laser systems that provide high power laser beams having preselected wavelengths and characteristics to optimize or enhance laser beam performance in predetermined environments, conditions and use requirements. In particular, lasers, methods and systems that relate to, among other things, Raman lasers, up conversion lasers, wavelength conversion laser systems, and multi-laser systems that are configured to match and create specific and predetermined wavelengths at specific points along an optical path having varying requirements along that path.

A laser pumping method pumps a primary amount of energy into a laser medium to populate an intermediate level near an upper laser level. A lesser amount of energy is pumped into the laser medium to populate an excited level that lies above the upper laser level and transfers atomic or molecular population to the upper laser level by a nonradiative process. A laser device includes a laser medium supporting four levels, including a lower laser level, an upper laser level, an excited level above the laser level from which population transfers to the upper laser level via nonradiative transition, and an intermediate level within a few kT of the upper laser level.