As an extension of the ideas of Hanbury-Brown and Twiss, a method is proposed to eliminate the phase noise of white chaotic light in the regime where it is dominant, and to measure the much smaller Poisson fluctuations from which the incoming flux can be reconstructed. The best effect is achieved when the timing resolution is finer than the inverse bandwidth of the spectral filter. There may be applications to radio astronomy at the phase noise dominated frequencies of 1 − 10 GHz, in terms of potentially increasing the sensitivity of telescopes by an order of magnitude.

The spontaneous length fluctuation of optical fibres caused by mechanical dissipation is analysed using a one-dimensional model based on the Fluctuation-Dissipation Theorem. Scale estimate shows evidence that the 1/f thermal noise originated from this fluctuation dominates at low frequencies in fibre interferometers and fibre cavities.

A general framework based on the fluctuation-dissipation theorem has been outlined for the study of the spontaneous thermal fluctuations in optical fibers. The goal is to seek a unified scheme to analyze the two types of intrinsic noises found in fiber lasers and interferometric fiber-optic sensors, namely, the thermoconductive noise and the thermomechanical noise. Some outstanding questions in the current theories are addressed. These include: (a) the underlying relation between the thermoconductive and the thermomechanical noises, (b) the lack of a fully disclosed theory for the thermoconductive noise in passive fibers, and (c) the low-frequency restriction in the current theory of the thermomechanical noise. Specific analyses based on the proposed approach find excellent agreement with existing theories.

To combat the rise of antibiotic resistant bacteria, it is essential to look upon other therapeutic solutions that do not solely depend upon conventional antibiotics. Here, we have designed a combinational therapeutic approach that kills bacteria with the conjunction of photothermal (PT) and antibiotic therapy. A near‐infrared (NIR) laser activated targeted drug delivery nano‐assembly delivers antibiotic as well as offer PT therapy (PTT). The synergistic application of both therapies increases the efficacy of treatment. The protected delivery of antibiotic and its release in the proximity of the bacteria surface reduces off‐target toxicity and reduce the efficacious dosage. Core of the nano‐assembly is composed of NIR active gold nanorods (GNRs) coated with a mesoporous silica nanoparticle (MSNP), which serves as a carrier for an anti‐tuberculosis drug bedaquiline (BDQ). The assembly was wrapped within a thermo‐sensitive liposome (TSL) conjugated to mycobacteria‐targeting peptide: NZX, GNR@MSNP@BDQ@TSL@NZX. NZX mediates adhesion of final nano‐assembly on mycobacteria surface. Upon NIR laser irradiation GNRs convert photo energy of the laser to localized heat, which melts TSL triggering release of BDQ. Antibacterial activity of final nano‐assembly against Mycobacterium smegmatis (Msmeg) was 20 folds more efficacious than the free drug equivalent. The final nano‐assembly could also successfully inhibit the growth of intracellular mycobacteria residing in lung cells.

Optical sampling by cavity tuning (OSCAT) enables cost-effective realization of fast tunable optical delay using a single femtosecond laser. We report here a dynamic model of OSCAT, taking into account the continuous modulation of laser repetition rates. This allows us to evaluate the delay scan depth under high interferometer imbalance and high scan rates, which cannot be described by the previous static model. We also report the demonstration of remote motion tracking based on fast OSCAT. Target vibration as small as 15 µm peak to peak and as fast as 50 Hz along line-of-sight has been successfully detected at an equivalent free-space distance of more than 2 km.