A confocal optical protractor for simultaneously measuring roll angle, pitch angle and yaw angle of an element that includes a tunable laser source generating a laser beam and an SPPR device responsive to the laser beam. The protractor also includes a beam splitter receiving and splitting an output beam from the SPPR device, and a lens being responsive to and projecting the split beam onto the element and being responsive to a reflected beam from the element. The protractor further includes a measurement detector responsive to the reflected beam from the element, where the reflected beam is imaged by the lens onto the measurement detector, and a processor receiving and processing image data from the measurement detector and generating the pitch, yaw and roll angles from the data, where the image data includes an orientation of an vortex intensity pattern in the split beam.

A confocal optical protractor for simultaneously measuring roll angle, pitch angle and yaw angle of an element that includes a tunable laser source generating a laser beam and an SPPR device responsive to the laser beam. The protractor also includes a beam splitter receiving and splitting an output beam from the SPPR device, and a lens being responsive to and projecting the split beam onto the element and being responsive to a reflected beam from the element. The protractor further includes a measurement detector responsive to the reflected beam from the element, where the reflected beam is imaged by the lens onto the measurement detector, and a processor receiving and processing image data from the measurement detector and generating the pitch, yaw and roll angles from the data, where the image data includes an orientation of an vortex intensity pattern in the split beam.

A method for simultaneously measuring roll angle, pitch angle and yaw angle of an element. The method includes directing a laser beam into a spiral phase plate resonator (SPPR) device to generate an optical vortex intensity pattern having a centroid and radial light peaks. The method reflects the laser beam off of the element after it has propagated through the SPPR device so that the laser beam is directed onto a camera that generates images of the optical vortex intensity pattern. The method determines a location of the centroid in the images, determines integrated counts along a radial direction from the centroid in the images, and determines a location of the radial light peaks in the images using the integrated counts. The method changes the frequency of the laser beam to rotate the radial light peaks, and estimates the roll angle of the element from the change in frequency.

A multi-clad optical fiber design is described in order to provide low optical loss, a high numerical aperture (NA), and high optical gain for the fundamental propagating mode, the linearly polarized (LP) 01 mode in the UV and visible portion of the optical spectrum. The optical fiber design may contain dopants in order to simultaneously increase the optical gain in the core region while avoiding additional losses during the fiber fabrication process. The optical fiber design may incorporate rare-earth dopants for efficient lasing. Additionally, the modal characteristics of the propagating modes in the optical core promote highly efficient nonlinear mixing, providing for a high beam quality (M.sup.2<1.5) output of the emitted light.

An optical apparatus includes one or more pump sources situated to provide laser pump light, and a gain fiber optically coupled to the one or more pump sources, the gain fiber including an actively doped core situated to produce an output beam, an inner cladding and outer cladding surrounding the doped core and situated to propagate pump light, and a polymer cladding surrounding the outer cladding and situated to guide a selected portion of the pump light coupled into the inner and outer claddings of the gain fiber. Methods of pumping a fiber sources include generating pump light from one or more pump sources, coupling the pump light into a glass inner cladding and a glass outer cladding of a gain fiber of the fiber source such that a portion of the pump light is guided by a polymer cladding surrounding the glass outer cladding, and generating a single-mode output beam from the gain fiber.

A light source for an imaging system. The light source includes a microresonator laser array having opposing mirrors arranged substantially parallel to one another. A laser gain medium is between the opposing mirrors. An array of microrefractive elements is arranged to stabilize the microresonator. A pump laser's output is shaped by a lens that directs it toward the micro-resonator laser array. An output lens directs a plurality of laser beams from the microresonator laser array to be incoherently combined at an object to be illuminated.

An amplification optical fiber according to the present invention includes: a core doped with an active element, through which multi-mode light propagates; an inner cladding that surrounds the core and has a refractive index lower than that of the core; and an outer cladding that surrounds the inner cladding and has a refractive index lower than that of the inner cladding. The inner cladding has a polygonal outline in a cross section perpendicular to the longitudinal direction, and the inner cladding has a permanent twist applied by turning around the central axis of the core.

A manufacturing technique of ultra-wideband high gain optical fibers and devices is disclosed, including: (1) manufacturing a gain fiber, which is a composite structural optical fiber, having a core composed of a plurality of sets of sector structures distributed symmetrically or a plurality of concentric ring structures. The core is composed of at least two kinds of rare-earth-ion-doped glass, and luminescence centers are located in different sector or ring structure regions; and (2) constructing a fiber laser: using the gain fiber, selectively exciting rare earth ions in different regions in the core by controlling a shape of pump light spot, and combining with fiber grating pairs to realize a tunable laser output. The present disclosure can manufacture gain fibers with high-gain and ultra-wideband characteristics by combining the design of the fiber structure and the control of the light field of the pump light.

A collinear T-cavity VECSEL system generating intracavity Hermite-Gaussian modes at multiple wavelengths, configured to vary each of these wavelengths individually and independently. A mode converter element and/or an astigmatic mode converter is/are aligned intracavity to reversibly convert the Gaussian modes to HG modes to Laguerre-Gaussian modes, the latter forming the system output having any of the wavelengths provided by the spectrum resulting from nonlinear frequency-mixing intracavity (including generation of UV, visible, mid-IR light). The laser system delivers Watt-level output power in tunable high-order transverse mode distribution.

A wavelength selection method for a tunable laser includes: obtaining a target wavelength; and calculating target resistance values of two thermistors, respectively, corresponding to the target wavelength. Each of the two thermistors is used to monitor the temperature of a corresponding one of two wavelength selection components. Each of the target resistance values is calculated according to a relationship between a wavelength drift and a resistance change of the corresponding thermistor and according to an initial wavelength and an initial resistance value of the corresponding thermistor corresponding to the initial wavelength. The method further includes: heating the two wavelength selection components to control their temperatures until real-time resistance values of the two thermistors reach the target resistance values, respectively; and stabilizing the real-time resistance values at the target resistance values and outputting a laser beam having the target wavelength.