Optical gain mediums are required for lasing devices and high intensity optical systems across a wide range of applications. A method for achieving optical gain includes an optical gain medium having colloidal quantum fountains includes providing pump radiation to the gain medium. The electrons of the colloidal quantum fountains are promoted from a valence band to an excited state in a conduction band of the colloidal quantum fountains. Seed radiation is provided to the gain medium and electrons of the quantum fountains are de-excited by the seed radiation through stimulated emission from the excited state to a lower energy state of the conduction band, thereby providing optical gain.

Provided is a laser oscillation element including a cholesteric liquid crystal layer, in which even in a case where the intensity of excitation light is weak, laser oscillation can be induced. The laser oscillation element includes a cholesteric liquid crystal layer obtained by cholesteric alignment of a liquid crystal compound, in which in a cross-section of the cholesteric liquid crystal layer observed with a scanning electron microscope, bright portions and dark portions derived from the cholesteric liquid crystalline phase are tilted with respect to a main surface of the cholesteric liquid crystal layer, the cholesteric liquid crystal layer includes a colorant that emits light by excitation, and a luminescence wavelength range of the colorant and a selective reflection wavelength range of the cholesteric liquid crystal layer at least partially overlap each other.

A single-mode micro-laser based on a single whispering gallery mode optical microcavity and a preparation method thereof described includes: preparing a desired single whispering gallery mode optical microcavity doped with rare earth ions or containing a gain material such as quantum dots, wherein an optical microcavity configuration include a micro-disk cavity, a ring-shaped microcavity, and a racetrack-shaped microcavity; a material type include lithium niobate, silicon dioxide, silicon nitride, etc.; preparing an optical fiber cone or an optical waveguide of a required size which can excite high-order modes of the optical microcavity, such as a ridge waveguide and a circular waveguides; and coupling, integrating, and packaging the optical fiber cone or the optical waveguide with the microcavity. A pump light is coupled to the optical fiber cone or the optical waveguide to excite a compound mode with a polygonal configuration.

A nanoscale circuit has an optical antenna receiving the radiation from a mode-locked laser and it responds by transmitting selected microwave or terahertz frequencies with a separate orthogonal antenna. Only MIM diodes, low-pass filters, and a load resistor are used to generate, separate, and transmit at the harmonics of the laser pulse-repetition rate.

Disclosed are photonic particles and methods of using particles in biological samples. The particles are configured to emit laser light when energetically stimulated by, e.g., a pump source. The particles may include a gain medium with inorganic materials, an optical cavity with high refractive index, and a coating with organic materials. The particles may be smaller than 3 microns along their longest axes. The particles may attach to each other to form, e.g., doublets and triplets. The particles may be injection-locked by coupling an injection beam into a particle while pumping so that an injection seed is amplified to develop into laser oscillation. A microscopy system may include a pump source, beam scanner, spectrometer with resolution of less than 1 nanometer and acquisition rate of more than 1 kilohertz, and spectral analyzer configured to distinguish spectral peaks of laser output from broadband background.

A laser whose emission is modulated by ultrasound is presented. The laser is usually micron-sized. In response to ultra-sound modulation, the laser emission increases and decreases. Such a change in emission can be detected by external optical detectors. This type of laser can be used as a new type of imaging modality, in which laser emission in combination with sound waves or ultra-sound waves, is used for imaging Laser emission has a much narrower spectral linewidth and stronger intensity than fluorescence and therefore is able to achieve higher sensitivity, whereas sound waves are used to provide a better spatial resolution of the laser emission from the laser. In ultrasound modulated laser based imaging, multiple lasers can be placed inside cells or tissues.

An active medium piece (109), which has been taken out using a nanoprobe (108), is processed so as to match the shape of a nanoslot (104), and thus an active medium small piece (111) that is smaller than the active medium piece (109) is formed (a fourth step). For example, irradiation with an ion beam (110) is performed so that the active medium piece (109) is shaped (processed) into an active medium small piece (111) that has a three-dimensional shape suitable for being placed in the nanoslot (104). The active medium piece (109) is processed into the active medium small piece (111) in the state of being held by the nanoprobe (108).

Methods for synthesizing fibers having nanoparticles therein are provided, as well as preforms and fibers incorporating nanoparticles. The nanoparticles may include one or more rare earth ions selected based on fluorescence at eye-safer wavelengths, surrounded by a low-phonon energy host. Nanoparticles that are not doped with rare earth ions may also be included as a co-dopant to help increase solubility of nanoparticles doped with rare earth ions in the silica matrix. The nanoparticles may be incorporated into a preform, which is then drawn to form fiber. The fibers may beneficially be incorporated into lasers and amplifiers that operate at eye safer wavelengths. Lasers and amplifiers incorporating the fibers may also beneficially exhibit reduced Stimulated Brillouin Scattering.

Disclosed is a terahertz laser device based on phonon vibration excitation, including a resonant cavity composed of a hollow waveguide made of a composite film and optical lenses at both ends of the waveguide, where M represents nano-metal particles. A zinc oxide mesomorphic microsphere is used herein as a source, symmetric stretching vibration of nanosheets on the zinc oxide microsphere is excited and induced by a laser and is transmitted through elastic and electric coupling among the nanosheets, and a terahertz wave with a frequency of 0.36 THz is radiated by means of phonon vibration; moreover, the zinc oxide mesomorphic microspheres and the nano-metal particles are mixed evenly to produce a strong local electric field a few nanometers nearby a surface of the metal particle by taking advantage of a surface-enhanced Raman effect of the nano-metal particles, a nanocantilever of the ZnO mesomorphic microsphere is greatly changed in polarizability with ample contact of the nano-metal particles and the ZnO mesomorphic microspheres, and thus the terahertz radiation power thereof is enhanced.

Methods for synthesizing fibers having nanoparticles therein are provided, as well as preforms and fibers incorporating nanoparticles. The nanoparticles may include one or more rare earth ions selected based on fluorescence at eye-safer wavelengths, surrounded by a low-phonon energy host. Nanoparticles that are not doped with rare earth ions may also be included as a co-dopant to help increase solubility of nanoparticles doped with rare earth ions in the silica matrix. The nanoparticles may be incorporated into a preform, which is then drawn to form fiber. The fibers may beneficially be incorporated into lasers and amplifiers that operate at eye safer wavelengths. Lasers and amplifiers incorporating the fibers may also beneficially exhibit reduced Stimulated Brillouin Scattering.