An apparatus for measuring time-resolved optical spectrum includes a light source, a sensor for collecting, forming, manipulating and measuring the intensity of the optical radiation, and a controller coupled to the light source and sensor. The sensor includes at least one optical delay element to provide a time delay to a first portion of the optical radiation. The sensor arrangement further includes an optical spectral disperser to split the delayed first portion and the second portion of the optical radiation into dispersed radiation having a plurality of wavelengths, and a sensor element configured to receive each wavelength of the dispersed radiation on a different spatial region, and measure the light intensity associated with each wavelength of the dispersed radiation. The controller collects the light intensity associated with each wavelength of the dispersed radiation measured by the sensor element to form a time-resolved optical spectrum.

Spectrometers include an optical assembly with optical elements arranged to receive light from a light source and direct the light along a light path to a multi-element detector, dispersing light of different wavelengths to different spatial locations on the multi-element detector. The optical assembly includes: (i) a collimator arranged in the light path to receive the light from the light source, the collimator including a mirror having a freeform surface; (2) a dispersive sub-assembly including an echelle grating, the dispersive sub-assembly being arranged in the light path to receive light from the collimator; and (3) a Schmidt telescope arranged in the light path to receive light from the dispersive sub-assembly and focus the light to a field, the multi-element detector being arranged at the field.

A system for a high resolution optical spectrum analyzer (OSA) using an efficient multi-pass configuration is disclosed. The system may include an entrance slit to allow inward passage of an optical beam. The system may also include a grating element to diffract the optical beam. The system may further include a retroreflective element to retroreflect the optical beam. The system may also include a mirror to reflect the optical beam. The system may include an exit slit, which in some examples may be adjacent to the entrance slit. The exit slit may allow outward passage of the optical beam for a high resolution optical measurement.

Spectrometers include an optical assembly with optical elements arranged to receive light from a light source and direct the light along a light path to a multi-element detector, dispersing light of different wavelengths to different spatial locations on the multi-element detector. The optical assembly includes: (i) a collimator arranged in the light path to receive the light from the light source, the collimator including a mirror having a freeform surface; (2) a dispersive sub-assembly including an echelle grating, the dispersive sub-assembly being arranged in the light path to receive light from the collimator; and (3) a Schmidt telescope arranged in the light path to receive light from the dispersive sub-assembly and focus the light to a field, the multi-element detector being arranged at the field.

A system for a high resolution optical spectrum analyzer (OSA) using an efficient multi-pass configuration is disclosed. The system may include an entrance slit to allow inward passage of an optical beam. The system may also include a grating element to diffract the optical beam. The system may further include a retroreflective element to retroreflect the optical beam. The system may also include a mirror to reflect the optical beam. The system may include an exit slit, which in some examples may be adjacent to the entrance slit. The exit slit may allow outward passage of the optical beam for a high resolution optical measurement.

A spectral reflectometer includes a first substrate, a first light emitting element and a second light emitting element in which a height of a first light emitting portion which is the height from the first substrate to a first light emitting portion of the first light emitting element, which is installed on the first substrate and a height of a second light emitting portion which is the height from the first substrate to a second light emitting portion of the second light emitting element are different, and a light receiver that receives light, in which the second light emitting element having a high height of the second light emitting portion is installed at a position close to an optical axis of the light received by the light receiver from the first light emitting element having a low height of the first light emitting portion.

Provided are an apparatus and method for two-dimensional spectroscopy using frequency combs and optical resonators, with the apparatus including at least one cavity and a controller for controlling generating a pump excitation using at least two frequency combs, generating a probe excitation using at least one frequency comb, and generating a resonantly enhanced signal frequency comb via a nonlinear-optical response of the sample. All frequency combs are resonant with a transverse mode of the cavity, to generate cavity-enhanced two-dimensional spectroscopy signals.

An apparatus for measuring time-resolved optical spectrum includes a light source, a sensor for collecting, forming, manipulating and measuring the intensity of the optical radiation, and a controller coupled to the light source and sensor. The sensor includes at least one optical delay element to provide a time delay to a first portion of the optical radiation. The sensor arrangement further includes an optical spectral disperser to split the delayed first portion and the second portion of the optical radiation into dispersed radiation having a plurality of wavelengths, and a sensor element configured to receive each wavelength of the dispersed radiation on a different spatial region, and measure the light intensity associated with each wavelength of the dispersed radiation. The controller collects the light intensity associated with each wavelength of the dispersed radiation measured by the sensor element to form a time-resolved optical spectrum.

Provided are an apparatus and method for two-dimensional spectroscopy using frequency combs and optical resonators, with the apparatus including at least one cavity and a controller for controlling generating a pump excitation using at least two frequency combs, generating a probe excitation using at least one frequency comb, and generating a resonantly enhanced signal frequency comb via a nonlinear-optical response of the sample. All frequency combs are resonant with a transverse mode of the cavity, to generate cavity-enhanced two-dimensional spectroscopy signals.

A spectral reflectometer includes a first substrate, a first light emitting element and a second light emitting element in which a height of a first light emitting portion which is the height from the first substrate to a first light emitting portion of the first light emitting element, which is installed on the first substrate and a height of a second light emitting portion which is the height from the first substrate to a second light emitting portion of the second light emitting element are different, and a light receiver that receives light, in which the second light emitting element having a high height of the second light emitting portion is installed at a position close to an optical axis of the light received by the light receiver from the first light emitting element having a low height of the first light emitting portion.