Onyx Optics (United States)

Astronomical polarimetry is a powerful tool in the investigation of asymmetries, magnetic fields, and scattering phenomena in and around stars, planets, and galaxies and also in the study of interstellar and circumstellar media Ȧs polarimetry is a photon-starved technique, a polarimetric capability on the next-generation giant segmented mirror telescopes (GSMTs) will enable observations of fainter targets, thereby opening up a wealth of science that cannot be achieved with the current generation of large telescopes. We are investigating the feasibility of adding a polarimetric capability to one of the planned first-generation instruments for the Giant Magellan Telescope (GMT). Here, we present a study of incorporating polarimetric optics into ComCam, the GMT Commissioning Camera. We analyze the performance of the instrument after the integration of a waveplate and Wollaston prism into the pseudo-collimated beam. We also present a design for new ComCam camera optics that are optimized to accommodate the polarimetric optics. Using the technical requirements from the polarimetric science cases, this ‘GMT-Pol’ version of the instrument delivers seeing-limited performance over a wavelength range of 0.5-0.9 μm with a ∼ 2 arcmin field-of-view.

We report on the amplification of 10 ns pulses at 1030 nm wavelength to 10 J at 10 Hz pulse rate using adhesive-free bonded Yb:YAG gain medium slabs. The experiments confirmed that bonded slabs are capable of withstanding repeated temperature cycling down to 120 K as well as thermally-induced stresses arising during laser operation. During high energy operation the bonding interfaces did not suffer from laser-induced damage onset up to the operational fluence of 3.1 J/cm². The infrared beam was also converted to second harmonic. These experiments confirm the viability of AFB technology for the manufacture of large-sized YAG slabs from smaller starting components, thus overcoming current limitations imposed by conventional manufacturing techniques. We believe that this approach will pave the way towards energy scaling of high energy DPSSLs.

A Micro-lens Array (MLA) is an optical element in which multiple lens segments are integrated onto a single substrate. Traditional MLAs consist of segments with the same geometric shape arranged at regular intervals atop a planar surface. They are used for applications that include beam homogenization, to equalize light intensity distribution, and light field imaging to change post-exposure the optical configuration such as viewpoint and focal distance of the captured image data. However, the limitations imposed by the identical segment geometry and the regular arrangement pattern constrain the range of possible applications and their associated performance. In this paper, novel MLA geometries and design methods are introduced that enable new generation products. With this type of MLA, each segment can have a different free planar shape and freeform surface shape in height direction. The segments of MLA are designed with topology optimization method based on internal stresses, that allows unsupervised design of optical segments. The designed freeform segments can maximize the use of light the lens, according to the target illumination pattern and intensity defined by each segment.

We report on the amplification of 10 ns pulses to 10 J at a repetition rate of 10 Hz using adhesive-free bonded Yb:YAG. Results show that AFB is suitable for aperture scaling of high- energy lasers.

Solid cancers that metastasize to the lungs represent a major therapeutic challenge. Current treatment paradigms for lung metastases consist of radiation therapy, chemotherapies, and surgical resection, but there is no single treatment or combination that is effective for all tumor types. To address this, oncolytic myxoma virus (MYXV) engineered to express human tumor necrosis factor (vMyx-hTNF) was tested after systemic administration in an immunocompetent mouse K7M2-Luc lung metastatic osteosarcoma model. Virus therapy efficacy against pre-seeded lung metastases was assessed after systemic infusion of either naked virus or ex vivo-loaded autologous bone marrow leukocytes or peripheral blood mononuclear cells (PBMCs). Results of this study showed that the PBMC pre-loaded strategy was the most effective at reducing tumor burden and increasing median survival time, but sequential intravenous multi-dosing with naked virus was comparably effective to a single infusion of PBMC-loaded virus. PBMC-loaded vMyx-hTNF also potentially synergized very effectively with immune checkpoint inhibitors anti-PD-1, anti-PD-L1, and anti-cytotoxic T lymphocyte associated protein 4 (CTLA-4). Finally, in addition to the pro-immune stimulation caused by unarmed MYXV, the TNF transgene of vMyx-hTNF further induced the unique expression of numerous additional cytokines associated with the innate and adaptive immune responses in this model. We conclude that systemic ex vivo virotherapy with TNF-α-armed MYXV represents a new potential strategy against lung metastatic cancers like osteosarcoma and can potentially act synergistically with established checkpoint immunotherapies.

A new solution for building high power, solid state lasers for space flight is to fabricate the whole laser resonator in a single (monolithic) structure or alternatively to build a contiguous diffusion bonded or welded structure. Monolithic lasers provide numerous advantages for space flight solid-state lasers by minimizing misalignment concerns. The closed cavity is immune to contamination. The number of components is minimized thus increasing reliability. Bragg mirrors serve as the high reflector and output coupler thus minimizing optical coatings and coating damage. The Bragg mirrors also provide spectral and spatial mode selection for high fidelity. The monolithic structure allows short cavities resulting in short pulses. Passive saturable absorber Q-switches provide a soft aperture for spatial mode filtering and improved pointing stability. We will review our recent commercial and in-house developments toward fully monolithic solid-state lasers.

A laser diode (LD) cladding pumped single-mode 1030 nm laser has been demonstrated, in an adhesive-free bonded 40 μm core Yb:YAG crystalline fiber waveguide (CFW). A laser output power of 13.2 W at a wavelength of 1.03 μm has been achieved, for an input pump power of 39.5 W. The corresponded laser efficiency is 33.4%. The laser beam quality is confirmed to be near diffraction-limited, with a measured M2 = 1.02. A LD core pumped single-clad Yb:YAG CFW laser has also been demonstrated with a top-hat laser beam profile, with a laser output power of 28 W and a slope efficiency of 78%.

Raman and Terahertz spectroscopy are both widely used for their ability to safely and remotely identify unknown materials. Each approach has its advantages and disadvantages. Traditional Raman spectroscopy typically measures molecular energy transitions in the 200-5000cm -1 region corresponding to sub-molecular stretching or bending transitions, while Terahertz spectroscopy measures molecular energy transitions in the 1-200cm -1 region (30GHz 6THz) that correspond to low energy rotational modes or vibrational modes of the entire molecule. Many difficult to detect explosives and other hazardous chemicals are known to have multiple relatively strong transitions in this “Terahertz” (<200cm -1 , <6THz) regime, suggesting this method as a powerful complementary approach for identification. However, THz signal generation is often expensive, many THz spectroscopy systems are limited to just a few THz range, and strong water absorption bands in this region can act to mask certain transitions if great care isn't taken during sample preparation. Alternatively, low-frequency or “THz-Raman” spectroscopy, which covers the ~5cm -1 to 200cm -1 (150GHz - 6 THz) regions and beyond, offers a powerful, compact and economical alternative to probe these low energy transitions. We present results from a new approach for extending the range of Raman spectroscopy into the Terahertz regime using an ultra-narrow-band volume holographic grating (VHG) based notch filter system. An integrated, compact Raman system is demonstrated utilizing a single stage spectrometer to show both Stokes and anti-Stokes measurements down to <10cm -1 on traditionally difficult to detect explosives, as well as other chemical and biological samples.

We report on the unique highly-configurable wavelength tuning and switching properties of a tunable external cavity laser based on multiplexed volume holographic gratings (VHGs) and a micromirror device. The ultra-compact laser has a 3 THz bandwidth and exhibits single mode operation in either single or multiple wavelengths with narrow linewidth (&lt;7.5 MHz), and a switching rate of 0.66 kHz per wavelength. A prototype laser exhibited 40 mW of output power for wavelengths from 776 - 783 nm. The unique discrete-wavelength-switching features and low power consumption of this laser make it well suited as a source for continuous-wave (cw) terahertz signal generation in portable photomixing systems.

We have demonstrated a novel folded linear resonator for walk-off compensated (WOC) optical parametric oscillation (OPO) in a single ZGP crystal. The OPO uses the doubled ZGP crystal length in a WOC configuration while simplifying requirements on crystal alignment. With a Q-switched Ho:YAG laser as a pump source, a maximum output power of 2 W at a wavelength of 4.72 μm has been measured for a pump power of 11.9 W in a 15-mm long type-I phase-matched ZGP crystal. The measured OPO quantum slope efficiency is above 50%.