Observability of individual fluorescent molecules under a microscope has many applications in biology.1, 2 In particular, by grafting fluorophores to biomolecules, they can be tracked in real time in live cells for monitoring of their conformational changes and interactions with other molecules. In other words, singlemolecule imaging allows scientists to read the textbook of life pretty much as...

Background: External beam radiation therapy is often administered to patients implanted with silicone gel breast prosthesis. The aim of this study was to investigate the influence of silicone gel breast prosthesis on photon dose distributions. In the event of recurrence, the oncologist may be forced to irradiate through the prosthetic device. To quantify the dose enhancement or reduction below ...

We present a single-photon avalanche diode (SPAD) with a wide spectral range fabricated in an advanced 180 nm CMOS process. The realized SPAD achieves 20 % photon detection probability (PDP) for wavelengths ranging from 440 nm to 820 nm at an excess bias of 4 V, with 30 % PDP at wavelengths from 520 nm to 720 nm. Dark count rates (DCR) are at most 5 kHz, which is 30 Hz/μm2, at an excess bias of...

Fig1: (a) Femtosecond pump-probe results: D and ND 2PA coefficient of ZnSe versus the sum of pump and probe photon energies normalized to the bandgap: solid lines are theoretical model. (b) Log-log plot of the output voltage of a GaN diode vs. 5.6 μm (215 fs) input signal energy in the presence of temporally overlapped 390 nm gating pulses (100 fs) of various energies. The grey filled in square...

e report the design and characterisation of a 32x32 time to digital (TDC) converter plus single photon avalanche diode (SPAD) pixel array implemented in a 130nm imaging process. Based on a gated ring oscillator approach, the 10 bit, 50μm pitch TDC array exhibits a minimum time resolution of 50ps, with accuracy of ±0.5 LSB DNL and 2.4 LSB INL. Process, voltage and temperature compensation (PVT) ...

Experimental quantum key distribution through free-space channels requires accurate pointing-and-tracking to co-align telescopes for efficient transmission. The hardware requirements the sender and receiver could be drastically reduced by combining detection of bits spatial tracking signal using two-dimensional single-photon detector arrays. Here, we apply a CMOS avalanche diode array measure m...

background: the present work aims to study the out-of-field photon calculation accuracy of a commercial treatment planning system (tps), oncentra, for three-dimensional conformal radiotherapy (3d-crt) and intensity modulated radiation therapy (imrt) treatment techniques from elekta synergy medical linear accelerator. materials and methods: accuracy of individual out-of-field dose components was...

We present an efficient method for optimizing the spatial profile of entangled-photon wave function produced in a spontaneous parametric down conversion process. A deformable mirror that modifies a wavefront of a 404 nm CW diode laser pump interacting with a nonlinear β-barium borate type-I crystal effectively controls the profile of the joint biphoton function. The use of a feedback signal ext...

We present a resonant-cavity-enhanced Single Photon Avalanche Diode (SPAD) fabricated on a reflecting siliconon-insulator (SOI) substrate. The substrate incorporates a two period distributed Bragg reflector fabricated using a commercially available double-SOI process. The resonant-cavity-enhanced (RCE) SPAD detectors have peak photon detection efficiencies ranging from 41% at 780nm to 32% at 85...