A calibration material may be used to calibrate an optical sensor to help ensure that the optical sensor produces accurate measurements. In some examples, the calibration material may be used to calibrate both turbidity measurements made by an optical sensor and fluorometric measurements made by the same optical sensor. The calibration material may be an aqueous mixture that includes water in an amount greater than 70 percent by weight of the composition, inorganic, water-insoluble, light-scattering particles, and a viscosity modifier in an amount effective to maintain the inorganic, water-insoluble, light-scattering particles in suspension in the composition. The composition can be non-fluorescing when exposed to ultraviolet light. In addition, in some applications, the composition is formulated of food safe ingredients, allowing the composition to be used in facilities that process consumable foods and beverages.

Techniques are disclosed relating to fluorescence-based flow cytometry. A flow cytometer may include a partially-reflective surface configured to reflect a first portion of fluorescent emissions from a sample to a first optical sensor and direct a second, greater portion of fluorescent emissions from the sample to a second optical sensor and a controller configured to determine a value representing the intensity of the fluorescent emissions based on a first measurement taken by the first optical sensor, a second measurement taken by the second optical sensor, or both. A flow cytometer may include a baseplate with a first side and a second, opposing side with a flow cell, a laser, and a reflective surface disposed above the first side and an optical sensor and isolating material disposed below the second side. The reflective surface receives fluorescent emissions and reflects at least a portion through the baseplate to the optical sensor. A flow cytometer may include a flow cell, a laser, a first optical sensor positioned to measure scattered laser light, a second optical sensor positioned to measure fluorescent emissions, and a controller configured to adjust the measurements taken by the second optical sensor based on a comparison of measurements taken by the first optical sensor with expected measurements based on a known beam profile of the laser beam.

A waveguide sensor system is provided. The system includes a light source and a waveguide formed from a light transmitting material. Light from the light source enters the waveguide at an input area and travels within the waveguide by total internal reflection to an analyte area and light to be analyzed travels within the waveguide from the analyte area by total internal reflection to an output area. An optical sensor is coupled to the output area and is configured to interact with the light to be analyzed. The system includes a plurality of pores located along the outer surface within the analyte area and formed in the light transmitting material of the waveguide, and the pores are configured to enhance light interaction with the analyte within the analyte area. The pores and analyte area may be protected and/or enhanced with a hydrophobic layer overlaying the pores.

Techniques are disclosed relating to fluorescence-based flow cytometry. A flow cytometer may include a partially-reflective surface configured to reflect a first portion of fluorescent emissions from a sample to a first optical sensor and direct a second, greater portion of fluorescent emissions from the sample to a second optical sensor and a controller configured to determine a value representing the intensity of the fluorescent emissions based on a first measurement taken by the first optical sensor, a second measurement taken by the second optical sensor, or both. A flow cytometer may include a baseplate with a first side and a second, opposing side with a flow cell, a laser, and a reflective surface disposed above the first side and an optical sensor and isolating material disposed below the second side. The reflective surface receives fluorescent emissions and reflects at least a portion through the baseplate to the optical sensor. A flow cytometer may include a flow cell, a laser, a first optical sensor positioned to measure scattered laser light, a second optical sensor positioned to measure fluorescent emissions, and a controller configured to adjust the measurements taken by the second optical sensor based on a comparison of measurements taken by the first optical sensor with expected measurements based on a known beam profile of the laser beam.

A recording medium determination device includes a light emitter, a light detector, and a hardware processor. The light emitter emits inspection light to a recording medium. The light detector detects incident light including at least one of diffuse reflected light of the inspection light emitted to the recording medium and fluorescent light excited by the inspection light in the recording medium. The hardware processor makes a determination depending on a property of the recording medium based on a detection result of first incident light of the incident light in accordance with first inspection light of the inspection light and second incident light of the incident light in accordance with second inspection light of the inspection light obtained by the light detector. The second inspection light has an intensity whose peak wavelength is shorter than the peak wavelength of the first inspection light.

Techniques are disclosed relating to fluorescence-based flow cytometry. A flow cytometer may include a partially-reflective surface configured to reflect a first portion of fluorescent emissions from a sample to a first optical sensor and direct a second, greater portion of fluorescent emissions from the sample to a second optical sensor and a controller configured to determine a value representing the intensity of the fluorescent emissions based on a first measurement taken by the first optical sensor, a second measurement taken by the second optical sensor, or both. A flow cytometer may include a baseplate with a first side and a second, opposing side with a flow cell, a laser, and a reflective surface disposed above the first side and an optical sensor and isolating material disposed below the second side. The reflective surface receives fluorescent emissions and reflects at least a portion through the baseplate to the optical sensor. A flow cytometer may include a flow cell, a laser, a first optical sensor positioned to measure scattered laser light, a second optical sensor positioned to measure fluorescent emissions, and a controller configured to adjust the measurements taken by the second optical sensor based on a comparison of measurements taken by the first optical sensor with expected measurements based on a known beam profile of the laser beam.

An apparatus (100) for optically characterizing a textile sample (106) comprises a presentation subsystem (102) comprising a viewing window (108). A radiation subsystem (114) comprises a radiation source (120) for directing a first, ultraviolet radiation (122) and a second, visible radiation (123) toward the sample (106), and causing the sample (106) to produce a fluorescent radiation (124) and a reflected radiation (125). A sensing subsystem (126) comprises an imager (130) for capturing the fluorescent radiation (124) and the reflected radiation (125) in an array of pixels (408). A control subsystem (132) comprises a processor (136) for controlling the presentation subsystem (102), the radiation subsystem (114), and the sensing subsystem (126), and for creating a fluorescent and reflected radiation image (400) containing both spectral information and spatial information in regard to the fluorescent radiation (124) and the reflected radiation (125).

An apparatus (100) for optically characterizing a textile sample (106) comprises a presentation subsystem (102) comprising a viewing window (108). A radiation subsystem (114) comprises a radiation source (120) for directing a first, ultraviolet radiation (122) and a second, visible radiation (123) toward the sample (106), and causing the sample (106) to produce a fluorescent radiation (124) and a reflected radiation (125). A sensing subsystem (126) comprises an imager (130) for capturing the fluorescent radiation (124) and the reflected radiation (125) in an array of pixels (408). A control subsystem (132) comprises a processor (136) for controlling the presentation subsystem (102), the radiation subsystem (114), and the sensing subsystem (126), and for creating a fluorescent and reflected radiation image (400) containing both spectral information and spatial information in regard to the fluorescent radiation (124) and the reflected radiation (125).

The synthesis of AgInS.sub.2 based quantum dots and their use as fluorometric probes for the selective detection of nitroaromatic explosive chemicals, without the use of ligands specific to nitroaromatic explosive chemicals. These quantum dots allow the detection of nitroaromatic explosive molecules by eye. The present invention also represents a simple patterning method for quantum dots on substrates, including low cost filter paper. The ease of fabrication, use of less toxic materials, and the selectivity to nitroaromatic explosive chemicals results in a practical solution to the development of a portable fluorescent probe based on quantum dots for the detection of nitroaromatic explosive chemicals.

A calibration material may be used to calibrate an optical sensor to help ensure that the optical sensor produces accurate measurements. In some examples, the calibration material may be used to calibrate both turbidity measurements made by an optical sensor and fluorometric measurements made by the same optical sensor. The calibration material may be an aqueous mixture that includes water in an amount greater than 70 percent by weight of the composition, inorganic, water-insoluble, light-scattering particles, and a viscosity modifier in an amount effective to maintain the inorganic, water-insoluble, light-scattering particles in suspension in the composition. The composition can be non-fluorescing when exposed to ultraviolet light. In addition, in some applications, the composition is formulated of food safe ingredients, allowing the composition to be used in facilities that process consumable foods and beverages.