A method of calibrating a driving parameter of an optical component across an operating wavelength range of the component. The method comprises placing a layer of material in a light path, the layer of material being substantially planar and substantially transparent and having a thickness of the order of wavelengths in said range and operating said component to vary said driving parameter whilst detecting light transmitted through said layer of material to obtain driving parameter versus light intensity data. The obtained data is then compared with characterizing data previously derived for said layer of material in order to calibrate said driving parameter.

A Raman spectroscopy method includes acquiring a first spectrum of a sample by performing exposure over a first time period in Raman spectroscopy of the sample, calculating a first Raman signal intensity of the first spectrum acquired, calculating a second time period from the first time period based on the ratio of the first Raman signal intensity calculated to a second Raman signal intensity that is a Raman signal intensity required for the Raman spectroscopy, the second time period being an exposure time period required for acquiring the second Raman signal intensity, and acquiring a second spectrum of the sample by performing exposure over the second time period calculated.

An optical measurement probe for capturing a spectral response through an intervening material emitting unwanted background radiation includes: a first lens configured to receive light and collimate the light into a collimated excitation beam defining a first aperture; an objective element for focusing the collimated excitation beam to a point or region in a sample through the intervening material, wherein the objective element also receives light scattered by the sample and the intervening material and collimates the scattered light into a collimated collection beam defining a second aperture; and a blocking element within the collimated collection beam for removing the light scattered by the intervening material from the collimated collection beam received from the sample, wherein the second aperture defined by the collimated collection beam is at least two times greater than the first aperture defined by the collimated excitation beam.

A polychromator system comprising: an optical element defining an aperture; a collimation mirror for receiving light via the aperture and reflecting substantially collimated light; at least a first dispersive optical component and a second dispersive optical component, each configured to disperse the substantially collimated light received from the collimation mirror by different amounts for different wavelengths and to provide cross-dispersed light having different wavelengths of light spaced along a first and second axis; and a focus mirror positioned to focus the cross-dispersed light onto a 2-D array detector to provide a plurality of aperture images of the aperture at a respective plurality of regions of the detector, each of the plurality of aperture images associated with a respective wavelength of the cross-dispersed light. Either one or both of the collimation mirror and the focus mirror is a freeform mirror having a reflective surface configured to mitigate effects of optical aberrations of the polychromator system over a plurality of the wavelengths of the cross-dispersed light along the first axis and the second axis and thereby optimise the resolution of the plurality of aperture images associated with the plurality of the wavelengths along the first axis and the second axis.

A remote sampling sensor for determining characteristics of a sample includes measurement optics and an insertion probe. The measurement optics are configured to emit light and detect returned light. The insertion probe includes a chamber, the chamber being configured to permit the sample to enter the chamber, an insertion tip at a distal end of the insertion probe, and a retro-reflective optic adjacent the insertion tip. The retro-reflective optic is configured to return the light from the measurement optics through the chamber to the measurement optics. The insertion probe is configured to be remotely located from the measurement optics.

Systems and methods are provided for measuring the mechanical properties of ocular tissue, such as the lens or corneal tissue, for diagnosis as well as treatment monitoring purposes. A laser locking feedback system is provided to achieve frequency accuracy and sensitivity that facilitates operations and diagnosis with great sensitivity and accuracy. Differential comparisons between eye tissue regions of a patient, either on the same eye or a fellow eye, can further facilitate early diagnosis and monitoring.

In a method of measuring moisture in corn, an ear of corn is operatively coupled to a moisture meter and an amount of moisture is determined while the ear of corn is being grown on a corn plant. The moisture meter can use a spectrometry to determine the amount of moisture in the corn. A moisture meter includes a corn interface configured to conformingly engage the ear of corn when pressed against the ear of corn to form an optical seal about an opening through which the spectrometer determines the amount of moisture in the corn to inhibit ambient light from passing between the corn interface and the ear of corn into the at least one opening.

The present disclosure provides a scanning probe, a method and an apparatus for manufacturing the scanning probe. The scanning probe includes a base and a micro-tip disposed on an end of the base, wherein at least a section of the micro-tip comprises a lateral surface with a concavely curved generatrix. In the method, an end of a probe precursor is immersed in a corrosive solution by having a length direction of the probe precursor inclined with a liquid surface of the corrosive solution. The probe precursor is corroded by the corrosive solution while a corrosion current of the corroding is monitored. The probe precursor is moved away from the corrosive solution after a magnitude of the corrosion current has a plunge. The apparatus includes a container containing the corrosive solution, and a driving device configured to move the probe precursor in the container through a fastener.

A compact, catadioptric and athermal imaging spectrometer is disclosed. A telecentric light (1) incident from a slit (2) is folded or refracted by an object-side prism (3) to enter a plano-convex lens (4); after being refracted by the plano-convex lens (4) and a meniscus lens (5), and refracted and reflected by a thick catadioptric lens (6), said telecentric light is incident onto a convex grating (7) in the form of a convergent beam; and after said beam is diffracted, spectral division is implemented. The divergent beam is sequentially refracted and reflected by the thick catadioptric lens (6), and refracted by the meniscus lens (5) and the plano-convex lens (4) to enter an image-side prism (8). Said beam is folded or refracted and filtered, and imaged on a focal plane (10) to realize spectral imaging.

A method for enhancement of spontaneous Raman scattering (SRS) from gases comprising a multimode blue laser diode which receives feedback from a near concentric bidirectional multipass cavity in such a way as to generate a circulating power of order 100 W for a sample volume of 10 mm.sup.3. The feedback, provided via a volume Bragg grating, reduces the laser bandwidth to 4 cm.sup.−1. Spectra of spontaneous Raman scattering from ambient atmospheric air, detected collinearly with the pump, were recorded with a limit of detection below 1 part-per-million.