Steven Trpkovski

Nano-manipulation of diamond-based single photon sources

The ability to manipulate nano-particles at the nano-scale is critical for the development of active quantum systems. This paper presents a technique to manipulate diamond nano-crystals at the nano-scale using a scanning electron microscope, nano-manipulator and custom tapered optical fibre probes. The manipulation of a approximately 300 nm diamond crystal, containing a single nitrogen-vacancy centre, onto the endface of an optical fibre is demonstrated. The emission properties of the single photon source post manipulation are in excellent agreement with those observed on the original substrate.

A highly efficient two level diamond based single photon source

An unexplored diamond defect center that is found to emit stable single photons at a measured rate of 1.6 MHz at room temperature is reported. The center, identified in chemical vapor deposition grown diamond crystals, exhibits a sharp zero phonon line at 734 nm with a full width at half maximum of ∼4 nm. The photon statistics confirm that the center is a single emitter and provides direct evidence of a true two level single quantum system in diamond.

High-temperature-resistant chemical composition Bragg gratings in Er 3+ doped optical fiber

Chemical composition gratings (CCGs), unlike standard fiber Bragg gratings (FBGs), do not suffer a significant decrease in reflectance or an irreversible wavelength shift when they are exposed to elevated temperatures. To date, the growth of CCGs has been related to the fluorine content of the fibers in which they are written. It is shown that FBGs with high thermal stability, resembling CCGs, can be fabricated in Er3+-doped optical fibers that do not contain any fluorine.

Dual Temperature and Strain Sensor Using a Combined Fiber Bragg Grating and Fluorescence Intensity Ratio Technique in Er3+-doped Fiber.

A prototype dual temperature–strain point sensor has been demonstrated by combining a short length of erbium-doped fiber in close proximity to a fiber Bragg grating. By measurement of the green fluorescence intensity ratio in erbium (Er3+) and the Bragg wavelength shift of a fiber Bragg grating the temperature and strain are deduced. Calibrations reveal that the sensitivity of the fluorescence intensity ratio in Er3+-doped fiber to strain is near zero. Three alternative analysis methods were used; the conventional matrix method, and two variations of a technique that provides a better fit to the fluorescence intensity ratio temperature data using a quadratic. The quadratic methods considered two cases of the strain dependence of the fluorescence intensity ratio, namely, zero and linear. The matrix method showed standard deviations of 2.2 °C and 20.6 μe, while the quadratic fit with a linear strain dependence yielded 1.0 °C and 22.9 μe over temperature and strain ranges of 18–150 °C and 350–2534 μe, respec...

Er3+:Yb3+ doped fibre with embedded FBG for simultaneous measurement of temperature and longitudinal strain

A method for measuring temperature and strain simultaneously using a combination of the shift in a fibre Bragg grating and the fluorescence intensity ratio from Er3+:Yb3+ doped fibre is presented. This sensor scheme has the advantage of co-located measurement of temperature and strain as the Bragg grating is written into the Er3+:Yb3+ doped fibre. A number of these sensors were calibrated over temperature and strain ranges of 20–150 °C and 350–2530 μe, respectively, and the measurement data analysed using various techniques. Temperature and strain values inferred from the sensors during these calibrations showed rms errors in the order of 0.3 °C and 4.9 μe.

Dependence of the fluorescence lifetime on dopant concentration and temperature in praseodymium-doped fluoride glass

The effects of temperature and concentration on the fluorescence lifetime of the 3P0 excited state in praseodymium-doped ZBLAN glass were studied. Above a critical dopant concentration, at which the lifetime exhibits no temperature dependence, the fluorescence lifetime increases with increasing temperature while below this concentration, the fluorescence lifetime decreases with increasing temperature. This critical concentration is determined to be 6900±220 ppm from measurements of the lifetime for varying temperatures and concentrations.

Temperature and strain measurement using a combined fiber Bragg grating and fluorescence intensity ratio technique in Er /sup 3+/-doped fiber

Overcoming the temperature cross sensitivity inherent in optical fiber strain sensors is currently of much interest. Many groups are investigating this cross-sensitivity in Bragg grating (FBG) sensors by seeking ways to have both parameters determined simultaneously from two separate sensor elements having different temperature and strain responsivities. It is therefore of interest to take advantage of the strain insensitivity of the fluorescence intensity ratio (FIR) technique by splicing a length of rare-earth-doped fiber to a FBG sensor. This paper reports initial measurements of temperature and strain using the proposed sensing scheme, in erbium-doped fibre.

Processing of Diamond: Towards All-Diamond Integrated Optics

Diamond photonic devices present a range of opportunities due to their unique properties. This paper presents progress in the fabrication of diamond waveguides using reactive ion etching (RIE), as a step towards all-diamond optics.

Three parameter measurement using a single fiber Bragg grating inscribed in Er3+:Yb3+-codoped fiber

A fiber Bragg grating was written, using the phase mask technique, in a short length of Er3+:Yb3+-codoped fibre and its temperature and strain characteristics were investigated. Two of the three parameters of interest are associated with Bragg grating properties, namely the usual dip at the Bragg wavelength, λB, and an unexpected dip at ~2/3 λB that is the third harmonic of features within the grating having double the assumed periodicity. The third parameter is the fluorescence intensity ratio arising from a pair of transitions in Yb3+ ions. This arrangement consisting of three co-located sensors offers interesting possibilities for the simultaneous measurement of three parameters.

Temperature and concentration dependence of the lifetime of a praseodymium excited state in fluorozirconate glass

Summary form only given. A variety of optical fibre temperature sensors have been demonstrated which rely on the temperature dependence of rare earth doped glass spectra and excited state lifetimes. Excited state lifetimes are also affected by the dopant concentration and as a result, the optimisation of a sensor requires tradeoffs between signal strength, dopant concentration and length of fibre sensor element. We present a study of the temperature and concentration dependence of the /sup 3/P/sub 0/ state of Pr/sup 3+/ doped ZBLANP which is designed to elucidate these tradeoffs.