About the cover: Advanced Photonics Volume 2, Issue 1

Strongly interacting systems of atoms and photons are an important resource in many active areas of research, including quantum information science, quantum simulation, and metrology. Frequently, the strength of these interactions is enhanced by using an optical resonator to confine light to a small volume. In recent years, there have been efforts to replace traditional Fabry–Perot resonators, formed from macroscopic mirrors, with micro- and nano-fabricated systems, leveraging techniques and infrastructure from semiconductor manufacture to scalably produce high-quality, small mode volume waveguides and resonators. Of particular interest are nano-fabricated photonic crystals, in which very fine control over modal and dispersion properties is possible. Here I describe our efforts to reliably produce photonic crystal waveguides with guided modes designed to trap and interrogate an array of ultracold cesium atoms. Specifically, I present models capturing band placement, modal structure, finite photonic crystal effects, and waveguide input and output coupling; I discuss the techniques we use to fabricate our photonic crystal waveguides; and I describe our characterization capabilities and the packaging and installation of the waveguides into the atomic physics system.

In this thesis, nanometer scale semiconductor lasers and micrometer scale polymer based dye lasers are our focus in bringing the miniaturized lasers to applications in data transmission; ultra-small chemical / biological sensors; and ultra-compact spectroscopic sources. Combining the advantage of electrically driven semiconductor lasers and the advantage of a broad emission spectrum of dye molecules would utilize the highly dense multi-functional lab-on-a-chip by integrating microfluidic PCR, microfluidic fluorescent detection system, and compact visible and NIR detectors which are commercially available. On the other hand, in the meantime of pushing the size limit of the laser cavities, new phenomena with the nanoscale lasers enable further exploration and understanding in fundamental physics. In the first part of this thesis, two sub-micron scale semiconductor lasers are presented. The smallest lasers utilizing the disk structures—with diameters of approximately 600 nm—were realized in the InGaP/InGaAlP quantum well material system at room temperature, featuring ultra-small mode volumes of approximately 0.03 cubic?microns, and exhibiting single-mode operation at low threshold powers. And the first visible photonic crystal ultra-small mode volume lasers, with cavity volumes of approximately 0.01 cubic?microns, are realized in the same material system. They are ideally suited for use as spectroscopic sources and both of them can be lithographically tuned from 650 – 690 nm. In the second part of this thesis, two sub-millimeter-scale polymer-based dye lasers—a poly(dimethylsiloxane) (PDMS)-based mechanically tunable DFB dye laser and a poly(methylmethacrylate) (PMMA)-based second-order circular grating distributed feedback dye laser—are presented. Both of them are compatible with microfluidic technology, which gives freedom in integrating the lasers with the microfluidic chips. Compared to the soft lithography used in the PDMS-based dye laser, the nanoimprint lithography used in the PMMA-based dye laser would be more useful for fabricating ultra-small dye lasers and enabling mass production in the near future. At the end of the thesis, a nano-linewidth metal grating mask pattern transferred transient grating (MPT-TG) technique is described as a potential technique using the ultra-small lasers for molecular-dynamics study in solutions.

Dataset to support the publication: Drevinskas, R & Kazansky, P 2017, 'High-performance geometric phase elements in silica glass' APL Photonics. DOI: 10.1063/1.4984066High-precision three-dimensional ultrafast laser direct nanostructuring of silica glass resulting in multi-layered space-variant dielectric metasurfaces embedded in volume is demonstrated. Continuous phase profiles of nearly any optical component are achieved solely by the means of geometric phase. Complex designs of half-wave retarders with 90% transmission at 532 nm and >95% transmission at >1 µm, including polarization gratings with efficiency nearing 90% and computer generated holograms with phase gradient of ~0.8pi rad/µm, were fabricated. Vortex half-wave retarder generating single beam optical vortex with tunable orbital angular momentum of up to ±100ℏ is shown. High damage threshold of silica elements enables simultaneous optical manipulation of large number of micro-objects using high-power laser beams. Thus, the continuous control of torque without altering the intensity distribution was implemented in optical trapping demonstration with a total of 5 W average power, which is otherwise impossible with alternate beam shaping devices. In principle, the direct-write technique can be extended to any transparent material that supports laser assisted nanostructuring, and can be effectively exploited for the integration of printed optics into multi-functional optoelectronic systems.

<i>Advanced Photonics</i>, co-published by SPIE and Chinese Laser Press, is a highly selective, Gold Open Access, international journal publishing innovative research in all areas of optics and photonics, including fundamental and applied research.