We demonstrate a pyrometric contactless temperature sensor using a flexible fused silica fiber of 360 μm diameter for endoscopic/laparoscopic surgery equipment. The large bandwidth (up to several kilohertz), and the broad temperature range (from 35°C to 250°C) of the sensor can be instrumental for time-resolved analysis and control of laser ablation and electrothermal surgery procedures. Fused silica fibers, as opposed to dedicated MIR fibers, are non-degrading, low-cost and biocompatible. Through dual-band detection, we also demonstrate a ratiopyrometric measurement scheme, which improves the detection of hot-spots, providing a helpful tool for focused thermal processes observed, for example, in pulsed laser ablation.
A miniaturized non-contact laser ranging sensor for endoscopic inspection and surgery tools is demonstrated. The sensor can measure the absolute distance between the endoscopic tool and the tissue in the 0-20 mm range with an axial resolution of 5 µm based on frequency-modulated continuous wave interferometry. As a tunable laser source, a commercially available 850 nm VCSEL is wavelength-modulated via self-heating, achieving a tuning range of 2.5 nm at 2.9 kHz repetition rate. Once coupled into a single-mode fiber, the laser light is projected onto the tissue using a loosely-focusing, Φ350 μm GRIN lens located at the distal end of the probe. The spectrum of the light collected by the same GRIN lens on the return path, which encodes the tissue distance in a well-defined modulation frequency, is detected by a silicon photodetector. Due to its low-cost, small diameter, flexibility and simplicity this sensor can be integrated monolithically into an endoscope or employed as a stand-alone sensor operating through the working channel.
Multi-modal endomicroscopy is one of the most promising means to enable optical biopsy methods to attain the specificity and selectivity of conventional biopsy. However, the development of the complex opto-mechanical systems needs very high assembly tolerances, and robust, biocompatible and ultra-slim packaging solutions. Therefore, the prototyping and low-volume manufacturing of multi-modal endomicroscopes are often costly and time intensive processes.
We present the opto-mechanical design of a novel endomicroscope combining wide-field microscopy and 3D OCT, and demonstrate the advantages of 3D glass micro structuring based assembly and packaging in terms of optical performance and device miniaturization. Using ray-tracing based Monte Carlo simulations, we demonstrate that this precision leads to a significantly better optical performance compared to that offered by rival 3D machining techniques, such as the state-of-the-art 3D polymer printers and conventional micromachining based solutions.
A highly-integrated MEMS-based bimodal probe design with integrated piezoelectric fiber scanner for simul-
taneous endomicroscopy and optical coherence tomography (OCT) is presented. The two modalities rely on
spectrally-separated optical paths that run partially in parallel through a micro-optical bench system, which has
dimensions of only 13 x 2 x 3mm3 (l x w x h). An integrated tubular piezoelectric fiber scanner is used
to perform en face scanning required for three dimensional OCT measurements. This scanning engine has an
outer diameter of 0.9mm and a length of 9mm, and features custom fabricated 10 μm thick polyimide flexible
interconnect lines to address the four piezoelectric electrodes. As a platform combining a full-field and a scanning
imaging modality, the developed probe design constitutes a blue print for a wide range of multi-modal endoscopic