Laser cooling with a single laser beam and a planar diffractor

A planar triplet of diffraction gratings is used to transform a single laser beam into a four-beam tetrahedral magneto-optical trap. This `flat' pyramid diffractor geometry is ideal for future microfabrication. We demonstrate the technique by trapping and subsequently sub-Doppler cooling 87Rb atoms to 30microKelvin.Comment: 3 pages, 4 figure

Femtosecond synchronously in-well pumped vertical-external-cavity surface-emitting laser

We demonstrate the first synchronously in-well pumped vertical-external-cavity surface-emitting laser (VECSEL). Depending on the cavity mismatch, laser pulses with a duration from 1 ps to 7 ps at a repetition rate of 76 MHz were generated directly from the laser at 860 nm. The application of extra-cavity pulse compression further shortened the pulse to a duration of 210 fs providing a peak power of 226 W

Measurement of the relativistic Doppler shift in neon

The relativistic Doppler shift is measured by the counting of the frequency difference between two cw dye lasers. One laser is locked to a two-photon transition in a fast beam of neon, and the other is locked to the same two-photon transition in thermal neon. The experimental result is compared to the prediction of special relativity. The result is in excellent agreement with this theory. An accuracy of 4x10exp-5 is obtained, which provides the most accurate direct verification of time dilatation to date.Peer reviewe

Two-photon laser scanning fluorescence microscopy using photonic crystal fibre

We report the application of a simple yet powerful modular pulse compression system, based on photonic crystal fibres which improves upon incumbent twophoton laser scanning fluorescence microscopy techniques. This system provided more than a 7-fold increase in fluorescence yield when compared with a commercial two-photon microscopy system. From this, we infer pulses of infrared radiaton of less than 35 fs duration reaching the sample

Utilising diffractive optics towards a compact, cold atom clock

Laser cooled atomic samples have resulted in profound advances in precision metrology [1], however the technology is typically complex and bulky. In recent publications we described a micro-fabricated optical element, that greatly facilitates miniaturisation of ultra-cold atom technology [2], [3], [4], [5]. Portable devices should be feasible with accuracy vastly exceeding that of equivalent room-temperature technology, with a minimal footprint. These laser cooled samples are ideal for atomic clocks. Here we will discuss the implementation of our micro-fabricated diffractive optics towards building a robust, compact cold atom clock

Orientational effects on the amplitude and phase of polarimeter signals in double resonance atomic magnetometry

Double resonance optically pumped magnetometry can be used to measure static magnetic fields with high sensitivity by detecting a resonant atomic spin response to a small oscillating field perturbation. Determination of the resonant frequency yields a scalar measurement of static field (B_0) magnitude. We present calculations and experimental data showing that the on-resonance polarimeter signal of light transmitted through an atomic vapour in arbitrarily oriented $B_0$ may be modelled by considering the evolution of alignment terms in atomic polarisation. We observe that the amplitude and phase of the magnetometer signal are highly dependent upon B_0 orientation, and present precise measurements of the distribution of these parameters over the full 4 pi solid angle

Grating chips for quantum technologies

We have laser cooled3x10^6 87Rb atoms to 3uK in a micro-fabricated grating magneto-optical trap (GMOT), enabling future mass-deployment in highly accurate compact quantum sensors. We magnetically trap the atoms, and use Larmor spin precession for magnetic sensing in the vicinity of the atomic sample. Finally, we demonstrate an array of magneto-optical traps with a single laser beam, which will be utilised for future cold atom gradiometry

Experimental Demonstration of Optimal Unambiguous State Discrimination

We present the first full demonstration of unambiguous state discrimination between non-orthogonal quantum states. Using a novel free space interferometer we have realised the optimum quantum measurement scheme for two non-orthogonal states of light, known as the Ivanovic-Dieks-Peres (IDP) measurement. We have for the first time gained access to all three possible outcomes of this measurement. All aspects of this generalised measurement scheme, including its superiority over a standard von Neumann measurement, have been demonstrated within 1.5% of the IDP predictions