Methods and systems for measuring one or more properties of a sample are disclosed. The methods and systems can include multiplexing measurements of signals associated with a plurality of wavelengths without adding any signal independent noise and without increasing the total measurement time. One or more levels of encoding, where, in some examples, a level of encoding can be nested within one or more other levels of encoding. Multiplexing can include wavelength, position, and detector state multiplexing. In some examples, SNR can be enhanced by grouping together one or more signals based on one or more properties including, but not limited to, signal intensity, drift properties, optical power detected, wavelength, location within one or more components, material properties of the light sources, and electrical power. In some examples, the system can be configured for optimizing the conditions of each group individually based on the properties of a given group.

A system, wearable device, and method include a light emitter configured to emit light at a first wavelength of between approximately 900 and 1000 nanometers and at a second wavelength of approximately 1350 nanometers, a first light detector spaced at a first distance from the light emitter, and a second light detector spaced at a second distance from the light emitter, the second distance approximately twice the first distance. At least one of hydration and glycogen of muscle tissue is determinable based on a relationship between backscatter light from the muscle tissue as detected by the second light detector and backscatter light from non-muscle tissue as detected by the first light detector.

Disclosed herein is an all-digital phase and timing correction procedure for coherent averaging in dual-comb and multiheterodyne spectroscopy—applicable to any dual-comb spectroscopy setup. It can account for large frequency/phase instabilities of the used sources, yielding a significant reduction of the noise pedestal and an increase in signal-to-noise ratio (SNR) of the radio frequency (RF) beat notes. This technique is computationally efficient and can be conveniently implemented either as a post-processing algorithm or in a real-time data acquisition and processing platform without the necessity of adding any additional optical elements to the dual-comb spectroscopy system. By implementing this technique, the performance of any comb- or comb-like-source-based DCS system with a sufficient degree of mutual coherence between the optical modes can be improved in terms of SNR and number of spectroscopically-usable RF beat notes. The described technique is compatible with a DC-centered RF spectrum, where the negative frequencies are folded to the positive domain to double the number of beat notes within the detector bandwidth. The technique enables coherent averaging over extended time-scales even for free-running combs, thus increasing the sensitivity of absorption and dispersion DCS measurements.

Disclosed herein is an all-digital phase and timing correction procedure for coherent averaging in dual-comb and multiheterodyne spectroscopy—applicable to any dual-comb spectroscopy setup. It can account for large frequency/phase instabilities of the used sources, yielding a significant reduction of the noise pedestal and an increase in signal-to-noise ratio (SNR) of the radio frequency (RF) beat notes. This technique is computationally efficient and can be conveniently implemented either as a post-processing algorithm or in a real-time data acquisition and processing platform without the necessity of adding any additional optical elements to the dual-comb spectroscopy system. By implementing this technique, the performance of any comb- or comb-like-source-based DCS system with a sufficient degree of mutual coherence between the optical modes can be improved in terms of SNR and number of spectroscopically-usable RF beat notes. The described technique is compatible with a DC-centered RF spectrum, where the negative frequencies are folded to the positive domain to double the number of beat notes within the detector bandwidth. The technique enables coherent averaging over extended time-scales even for free-running combs, thus increasing the sensitivity of absorption and dispersion DCS measurements.

In some embodiments, a system comprises a head-mounted frame removably coupleable to the user's head; one or more light sources coupled to the head-mounted frame and configured to emit light with at least two different wavelengths toward a target object in an irradiation field of view of the light sources; one or more electromagnetic radiation detectors coupled to the head-mounted member and configured to receive light reflected after encountering the target object; and a controller operatively coupled to the one or more light sources and detectors and configured to determine and display an output indicating the identity or property of the target object as determined by the light properties measured by the detectors in relation to the light properties emitted by the light sources.

In some embodiments, a system comprises a head-mounted frame removably coupleable to the user's head; one or more light sources coupled to the head-mounted frame and configured to emit light with at least two different wavelengths toward a target object in an irradiation field of view of the light sources; one or more electromagnetic radiation detectors coupled to the head-mounted member and configured to receive light reflected after encountering the target object; and a controller operatively coupled to the one or more light sources and detectors and configured to determine and display an output indicating the identity or property of the target object as determined by the light properties measured by the detectors in relation to the light properties emitted by the light sources.

A sensor device may determine a first optical sensor value associated with a first displacement and a second optical sensor value associated with a second displacement, wherein the first displacement is between an emitter associated with the first optical sensor value and a sensing location used to determine the first optical sensor value, wherein the second displacement is between an emitter associated with the second optical sensor value and a sensing location used to determine the second optical sensor value, and wherein the first displacement is different from the second displacement. The sensor device may determine one or more measurements using the first optical sensor value and the second optical sensor value, wherein the one or more measurements relate to a first penetration depth associated with the first optical sensor value, and a second penetration depth associated with the second optical sensor value.

A sensor device may determine a first optical sensor value associated with a first displacement and a second optical sensor value associated with a second displacement, wherein the first displacement is between an emitter associated with the first optical sensor value and a sensing location used to determine the first optical sensor value, wherein the second displacement is between an emitter associated with the second optical sensor value and a sensing location used to determine the second optical sensor value, and wherein the first displacement is different from the second displacement. The sensor device may determine one or more measurements using the first optical sensor value and the second optical sensor value, wherein the one or more measurements relate to a first penetration depth associated with the first optical sensor value, and a second penetration depth associated with the second optical sensor value.

Methods and systems for measuring one or more properties of a sample are disclosed. The methods and systems can include multiplexing measurements of signals associated with a plurality of wavelengths without adding any signal independent noise and without increasing the total measurement time. One or more levels of encoding, where, in some examples, a level of encoding can be nested within one or more other levels of encoding. Multiplexing can include wavelength, position, and detector state multiplexing. In some examples, SNR can be enhanced by grouping together one or more signals based on one or more properties including, but not limited to, signal intensity, drift properties, optical power detected, wavelength, location within one or more components, material properties of the light sources, and electrical power. In some examples, the system can be configured for optimizing the conditions of each group individually based on the properties of a given group.

Methods and systems for measuring one or more properties of a sample are disclosed. The methods and systems can include multiplexing measurements of signals associated with a plurality of wavelengths without adding any signal independent noise and without increasing the total measurement time. One or more levels of encoding, where, in some examples, a level of encoding can be nested within one or more other levels of encoding. Multiplexing can include wavelength, position, and detector state multiplexing. In some examples, SNR can be enhanced by grouping together one or more signals based on one or more properties including, but not limited to, signal intensity, drift properties, optical power detected, wavelength, location within one or more components, material properties of the light sources, and electrical power. In some examples, the system can be configured for optimizing the conditions of each group individually based on the properties of a given group.