Single-mode, All-Solid-State Nd:YAG Laser Pumped UV Converter
In this paper, the status of a high-energy, all solid-state Nd:YAG laser pumped nonlinear optics based UV converter development is discussed. The high-energy UV transmitter technology is being developed for ozone sensing applications from space based platforms using differential lidar technique. The goal is to generate greater than 200 mJ/pulse with 10-50 Hz PRF at wavelengths of 308 nm and 320 nm. A diode-pumped, all-solid-state and single longitudinal mode Nd:YAG laser designed to provide conductively cooled operation at 1064 nm has been built and tested. Currently, this pump laser provides an output pulse energy of >1 J/pulse at 50 Hz PRF and a pulsewidth of 22 ns with an electrical-to-optical system efficiency of greater than 7% and a M(sup 2) value of <2. The single frequency UV converter arrangement basically consists of an IR Optical Parametric Oscillator (OPO) and a Sum Frequency Generator (SFG) setups that are pumped by 532 nm wavelength obtained via Second Harmonic Generation (SHG). In this paper, the operation of an inter cavity SFG with CW laser seeding scheme generating 320 nm wavelength is presented. Efforts are underway to improve conversion efficiency of this mJ class UV converter by modifying the spatial beam profile of the pump laser.
Qualification of the laser transmitter for the CALIPSO aerosol lidar mission
Space-based missions impose a unique set of requirements on laser designs. The development of the CALIPSO Laser Transmitter Subsystem (LTS) began with a successful lifetime test using the Risk Reduction Laser (RRL), followed with an intensive design validation phase using prototype flight hardware, and completed with formal qualification of the flight hardware. We will describe this process in more detail and review the issues encountered and lessons learned. From this experience we developed a set of guidelines for designing and building future space-based lasers.
Annual review article: Is it time to rethink the gender agenda in entrepreneurship research?
This article develops a critique of contemporary approaches to analysing the impact of gender upon entrepreneurial propensity and activity. Since the 1990s, increasing attention has been afforded to the influence of gender on women’s entrepreneurial behaviour; such analyses have highlighted an embedded masculinity within the entrepreneurial discourse which privileges men as normative entrepreneurial actors. While invaluable in revealing a prevailing masculine bias within entrepreneurship, this critique is bounded by positioning women as a proxy for the gendered subject. This is a potentially limiting analysis that does not fully recognise gender as a human property with myriad articulations enacted throughout entrepreneurial activity. To progress debate, we engage more deeply with the notion of gender as a multiplicity, exploring the implications of such for future studies of entrepreneurial activity.