Source light having a range of optical wavelengths is generated. The source light is split into sample light and reference light. The sample light is delivered into a sample, such that the sample light is scattered by the sample, resulting in signal light that exits the sample. The signal light and the reference light are combined into an interference light pattern having optical modes, each having a direct current (DC) component and at least one alternating current (AC) component. Different subsets of the optical modes of the interference light pattern are respectively detected, and analog signals representative of the optical modes of the interference light pattern are output. Pair of the analog signals are subtracted from each other, and differential analog signals are output. The sample is analyzed based on the differential analog signals.

An illustrative optical measurement system includes a light source configured to emit light directed at a target. The system further includes a detector configured to detect arrival times for photons of the light after the light is scattered by the target. The system further includes a temperature sensor configured to output a temperature signal representative of a temperature of the light source. The system further includes an optical sensor configured to output a power signal representative of an optical power level of the light emitted by the light source. The system further includes a driver circuit configured to output, based on the temperature signal and the power signal, an input current for the light source.

An in situ near infrared sensing unit includes a housing allowing the sensing unit to be inserted in a variety of media. A transparent window is formed in the sidewall of the housing. A sensing element is mounted inside the housing. The sensing element is configured to emit near infrared light provided from a light source external to the housing, and the sensing element is configured to collect near infrared light transmitted through the transparent window. A mirror is mounted in the housing at an angle with respect to the transparent window and opposite the sensing element. The angle allows the mirror to reflect the near infrared light, emitted by the sensing element, through the transparent window.

The present disclosure provides a method for trapping molecules with optical fiber tweezers based on phase transition and crystallization and a method for detecting a Raman spectrum of a persistent organic pollutant, belonging to the technical field of surface-enhanced Raman spectroscopy. Based on quite different solubilities of a substance to be detected in different solvents, dissolved phase small molecules to be detected are transformed into large size crystalline phase molecules through the physical process of phase transition and crystallization. Further, effective trapping of molecules to be detected that are not prone to bonding to noble metal nanoparticles in the vicinity of the noble metal nanoparticles can be achieved by combining the physical process of phase transition and crystallization with the physical trapping technique using optical fiber tweezers, so that the sensitivity of surface-enhanced Raman scattering (SERS) spectrum detection is significantly improved.

An apparatus for obtaining information regarding a biological structure(s) can include, for example a light guiding arrangement which can include a fiber through which an electromagnetic radiation(s) can be propagated, where the electromagnetic radiation can be provided to or from the structure. An at least partially reflective arrangement can have multiple surfaces, where the reflecting arrangement can be situated with respect to the optical arrangement such that the surfaces thereof each can receive a(s) beam of the electromagnetic radiations instantaneously, and a receiving arrangement(s) which can be configured to receive the reflected radiation from the surfaces which include speckle patterns.

An optical probe includes an optical housing, a transmitting lens and a receiving lens. The optical housing extends from a proximate end to an opposing distal end. The transmitting lens is disposed at the distal end and is configured to output a first transmitted signal beams having a first transmission axis and a second transmitted beam having a second transmission axis that is different from the first transmission axis. The receiving lens is disposed at the distal end and configured to receive the first and second reflected signal beams corresponding respectively to the first and second transmitted signal beams. The optical housing has formed therein a transmitting optical channel configured to communicate an input optical signal from the proximate end to the transmitting lens. A receiving optical channel separated from the transmitting optical channel communicates the first and second reflected signal beams to the proximate end.

An all-purpose device capable of in vitro spectral analysis of sunscreen compositions as well as diffuse reflectance spectroscopy (DRS) capabilities on human skin includes a fiber optic guide, a light source positioned at one end of the fiber optic guide, and a sunscreen substrate assembly positioned at another end of the fiber optic guide.

An optical apparatus (200) includes an outer jacket (230), common cladding (220), and multiple single mode fiber cores (210). The common cladding (220) is within the outer jacket (230) and is used as multimode fiber such that the outer jacket (230) clads the common cladding (220). The single mode fiber cores (210) are within the common cladding (220) such that the common cladding (220) clads the plurality of single mode fiber cores (210).

The invention is used to ascertain a sun protection factor for light, for example for cosmetics and sunscreens for which a sun protection factor (SPF) is specified. Two measurements of the light backscattering on the skin surface are carried out in vivo or in vitro or on skin models (animal skin models or artificial skin models) before and after applying the radiation protection means onto the skin, and the sun protection factor is ascertained therefrom. In contrast to standard methods used until now, the distance between the lighting surface and the detection surface on the skin is ascertained for the irradiation path of the measurement method. The skin lighting dose used during the measurement lies below harmful limits. The sun protection factor can be ascertained according to previous standards or for additional wavelengths or wavelength ranges (e.g. UVA, VIS, NIR, IR).

An apparatus for obtaining information regarding a biological structure(s) can include, for example a light guiding arrangement which can include a fiber through which an electromagnetic radiation(s) can be propagated, where the electromagnetic radiation can be provided to or from the structure. An at least partially reflective arrangement can have multiple surfaces, where the reflecting arrangement can be situated with respect to the optical arrangement such that the surfaces thereof each can receive a(s) beam of the electromagnetic radiations instantaneously, and a receiving arrangement(s) which can be configured to receive the reflected radiation from the surfaces which include speckle patterns.