A monolithic diamond Raman laser is reported. It utilizes a 13-mm radius of curvature lens etched onto the diamond surface and dielectric mirror coatings to form a stable resonator. The performance is compared to that of a monolithic diamond Raman laser operating in a plane-plane cavity. On pumping with a compact Q-switched laser at 532 nm (16 μJ pulse energy; 1.5 ns pulse duration; 10 kHz repetition-rate; M²<1.5), laser action was observed at the first, second, and third Stokes wavelengths (573 nm, 620 nm and 676 nm, respectively) in both cases. For the microlens cavity, a conversion efficiency of 84% was achieved from the pump to the total Raman output power, with a slope efficiency of 88%. This compares to a conversion efficiency of 59% and a slope efficiency of 74% for the plane-plane case. Total Raman output powers of 134 and 96 mW were achieved for the microlens and plane-plane cavities, respectively.

The variation in the Raman gain coefficient in single-crystal diamond for pump wavelengths between 355 and 1450 nm has been measured. Two techniques have been used: a pump-probe approach giving an absolute measurement and a stimulated Raman oscillation threshold technique giving a relative measurement. Both approaches indicate that the Raman gain coefficient is a linear function of pump wavenumber. With the pump polarised along a <111> direction in the crystal, the Raman gain coefficient measured by the pump-probe technique was found to vary from 7.6±0.8 for a pump wavelength of 1280 nm to 78±8 cm/GW for a pump wavelength of 355 nm. With the established dependence of the Raman gain coefficient on the pump wavelength, the Raman gain coefficient can be estimated at any pump wavelength within the spectral range from 355 up to 1450 nm.

Several groups within the IETF and IRTF have discussed the Handle System and its relationship to existing systems of identifiers. The IESG wishes to point out that these discussions have not resulted in IETF consensus on the described Handle System, nor on how it might fit into the IETF architecture for identifiers. Though there has been discussion of handles as a form of URI, specifically as a URN, these documents describe an alternate view of how namespaces and identifiers might work on the Internet and include characterizations of existing systems which may not match the IETF consensus view. AbstractThe Handle System is a general-purpose global name service that allows secured name resolution and administration over the public Internet. This document describes the protocol used for client software to access the Handle System for both handle resolution and administration. The protocol specifies the procedure for a client software to locate the responsible handle server of any given handle. It also defines the messages exchanged between the client and server for any handle operation.

A time-resolved Raman spectrometer is demonstrated based on a 256×8 CMOS SPAD line sensor and a 573 nm fiber-coupled diamond Raman laser delivering pulses with duration below 100 ps FWHM. The collected back scattered light from the sample is dispersed on the line sensor using a custom volume holographic grating having 1800 lines/mm. Efficient fluorescence rejection in the Raman measurements is achieved due to a combination of time gating on sub-100 ps-time scale and a 573 nm excitation wavelength. To demonstrate the performance of the spectrometer, fluorescent oil samples were measured. For organic sesame seed oil having a continuous wave mode fluorescence-to-Raman ratio of 10.5 and a fluorescence lifetime of 2.7 ns, a signal-to-distortion value of 76.2 was achieved. For roasted sesame seed oil having a continuous wave mode fluorescence-to-Raman ratio of 82 and a fluorescence lifetime of 2.2 ns, a signal-to-distortion value of 28.2 was achieved. In both cases, the fluorescence-to-Raman ratio was reduced by a factor of 24-25 owing to time gating. For organic oil, spectral distortion was dominated by dark counts while for the more fluorescent roasted oil, the main source of spectral distortion was timing skew of the sensor. With the presented post-processing techniques, the level of distortion could be reduced by 88-89 % for both samples. Compared to common 532 nm excitation, approximately 73 % lower fluorescence-to-Raman ratio was observed for 573 nm excitation when analyzing the organic sesame seed oil. Index Terms-Fluorescence rejection, Raman laser, Raman spectrometer, Raman spectroscopy, SPAD sensor, time-correlated single photon counting, time gating, timing skew I. INTRODUCTION AMAN spectroscopy is used in a wide range of fields including food and oil industries, mining industry, medical diagnostics, pharmacy, forensic science and archaeometry [1]

The design and fabrication of large radii of curvature micro-lenses in single crystal chemical vapour deposition diamond is described. An optimised photoresist reflow process and low selectivity inductively coupled plasma etching are used to actualize a uniform array of micro-lenses with radii of curvature of 13 mm or more and a high quality surface of a root-mean-square roughness of 0.18 nm. The processes developed have the potential to achieve diamond micro-lenses with an even larger radius of curvature. These new diamond micro-lenses enable the pulse energy scalable monolithic diamond Raman laser where a large radius of curvature of the micro-lenses is critical