Multimode fiber-based endoscopes have recently emerged as a tool for minimally invasive endoscopy in tissue, at depths well beyond the reach of multiphoton imaging. Here, we demonstrate label-free second-harmonic generation (SHG) microscopy through such fiber endoscope. We simultaneously fully control excitation polarization state and spatial distribution light tip, use this to implement polarization-resolved SHG imaging, which allows imaging identification structural proteins collagen...

Optical trapping is a well-established, decades old technology with applications in several fields of research. The most common scenario deals particles that tend to be centered on the brightest part optical trap. Consequently, forces keep particle away from dark zones beam. However, this not case when focused doughnut-shaped beam generates on-axis trapping. In system, intensity minima laser and bright annular lies periphery particle. Researchers have shown great interest phenomenon due its...

The interferometric acquisition of the transmission matrix (TM) a multimode optical fibre (MMF), which is at heart fibre-based endoscopic imaging methods, requires using reference beam. Attempts to use an internal reference, that provide in common pathway geometry through MMF itself, lead speckled intensity and consequential occurrence “blind spots”—locations where insufficient power wave inflicts strong measurement errors. Here we show combining relatively small number TMs, are measured...

Both thermal diffusivity and effusivity (or conductivity) are necessary to characterize the transport properties of a material. The flash method is most recognized procedure measure free-standing opaque plates. However, it fails simultaneously obtain conductivity). This due difficulty knowing total energy absorbed by sample surface after light pulse. In this work, we propose using in front-face configuration on two-layer system made unknown plate fluid known properties. We demonstrate that...

Here, we present a novel application of the shadowgraph technique for obtaining thermal diffusivity an opaque solid sample, inspired by orthogonal skimming photothermal beam deflection technique. This new variant utilizes shadow projected sample when put against collimated light source. The is then heated periodically another beam, giving rise to waves, which propagate across it and through its surroundings. Changes in refractive index surrounding media due heating distort shadow. phenomenon...

Controlling light at the tip of a multimode fiber holds great potential for sensing applications. Here, we present how by measuring transmission matrix, may produce cylindrical vector beam tip.

We present a versatile, robust and inexpensive setup for Nitrogen Vacancy center based sensing that enables automatized generation of large datasets to train machine learning algorithms towards fieldable advanced quantum magnetic field sensors.

Photothermal beam deflection is a well-established technique for measuring thermal diffusivity. In this technique, pump laser generates temperature variations on the surface of sample to be studied. These transfer heat surrounding medium, which may air or any other fluid. The medium in turn experiences change refractive index, will proportional field when distance small. A probe suffer due index periodical changes, usually monitored by means quadrant photodetector similar device aided...

We present a method to characterize vertical cracks in fast way using burst vibrothermography. In this technique the sample is excited by ultrasounds and, at defect, rubbing of contacting surfaces produces heat that can be detected as temperature rise surface an infrared camera. work, first we solution direct problem, i.e., calculation distribution produced source representing crack ultrasound burst, and choose information will used crack, namely, one thermogram timing-graph. Next address...

The four-wave mixing background generated in a GRIN multimode fiber when performing non-linear Raman imaging reduces the image contrast. Here we demonstrate composite probe to overcome this problem.

Multimode optical fiber (MMF) endoscopes have recently gained widespread attention as a novel tool for imaging deep within tissue using light microscopy. We here present method particle tracking through the MMF, which overcomes lack of fast enough wide-field fluorescence modality this type endoscope, namely discrete implementation orbital tracking. achieve biologically relevant speeds (up to 1.2 μm/s) despite slow SLM wavefront shaping. demonstrate accuracy λ/50 0.3 NA and show pinhole...

Burst vibrothermography is used to characterize vertical cracks.We excite the sample with a short ultrasound burst of constant intensity and we register evolution surface temperature during after burst.Among all this information, crack using thermogram obtained end (timing graph) at center thermograms.We have developed stabilized inversion algorithm retrieve area depth crack.Inversions experimental data samples containing calibrated heat sources confirm validity method.

We present a method for measurement of the thermal diffusivity metallic samples in form thin filaments, which is inspired both photothermal beam deflection and shadowgraph techniques.The utilizes shadow projected by sample when put against collimated light source (a probe beam).The then heated periodically another (the pump beam), giving rise to waves, propagate across it through its surroundings.Changes refraction index surrounding media due heating distort shadow.The periodical time...

We address the characterization of planar inner defects any inclination, using infrared thermography (IRT) with kind excitation that turns defect into a heat source (ultrasonic or eddy current).First, we calculate surface temperature distribution.Then, present multi-parametric fittings (dimensions, depth and inclination) noisy synthetic data to characterize defect.Finally, prepare 3D printed plastic parallelepiped samples containing graphite copper slabs are excited optically inductively,...

The thermal diffusivity of thin metallic filaments is measured by the photothermal beam deflection method using a digital camera and lock-in imaging processing methodologies in multibeam shadowgraph experimental configurations.

In recent years, great advances have been made in developing minimal footprint micro-endoscopes using multimode optical fibres (MMF) [1]. By employing wavefront shaping methods the seemingly random speckle pattern resulting from guiding of coherent light through an MMF can be formed into a diffraction limited spot. This enables implementation multiple laser scanning techniques. this work we show that approach employed to realize label-free non-linear microscopy techniques such as anti-Stokes...

A GRIN multimode fiber (125 μm diameter, 0.29 NA) is transformed into a laser scanning microscope using wave-front shaping on an SLM. We demonstrate label-free non-linear microscopy, namely coherent anti-Stokes Raman scattering (CARS) and SHG.