Design and fabrication of a miniature objective consisting of high refractive index zinc sulfide lenses for laser surgery

Abstract

A miniature laser ablation probe relying on an optical fiber to deliver light requires a high coupling efficiency objective with sufficient magnification in order to provide adequate power and field for surgery. A diffraction-limited optical design is presented that utilizes high refractive index zinc sulfide to meet specifications while reducing the miniature objective down to two lenses. The design has a hypercentric conjugate plane on the fiber side and is telecentric on the tissue end. Two versions of the objective were built on a diamond lathe—a traditional cylindrical design and a custom-tapered mount. Both received an antireflective coating. The objectives performed as designed in terms of observable resolution and field of view as measured by imaging a 1951 USAF resolution target. The slanted edge technique was used to find Strehl ratios of 0.75 and 0.78, respectively, indicating nearly diffraction-limited performance. Finally, preliminary ablation experiments indicated threshold fluence of gold film was comparable to similar reported probes.

Miniature, multi-dichroic instrument for measuring the concentration of multiple fluorophores

“…Instruments capable of spatially separating strong and weak intensity signals and coupling them to dedicated detectors with matching dynamic range, provide a strong alternative to the spectroscope-based setups for clinical measurements. Such system can become very compact for straight-forward adaptation to the clinical workflow [ 13 , 14 ]. Also, illumination and signal acquisition of such systems can be modulated in kHz frequency range.…”

Multi-Spectral Clinical Prototype for Fluorophore Detection

“…Multi-source and detector systems, provide a strong alternative to the spectroscope-based setups for clinical measurements. Such system can become very compact for straight-forward adaptation to the clinical work flow [21,22]. Also, illumination and signal acquisition of such systems can be modulated in kHz frequency range, allowing for more accurate background measurements and leading to improved SNRs and decreased photo-bleaching if used with 5-ALA.…”

Intrinsic High Refractive Index Siloxane–Sulfide Polymer Networks Having High Thermostability and Transmittance via Thiol–Ene Cross-Linking Reaction

“…As optical devices become more ubiquitous and complex, there arises increasing needs for new specialized functional materials. − One of the increasing interests is in high refractive index polymers (HRIPs) due to their numerous applications in optical materials including lenses, − encapsulants, − antireflective coatings, − and infrared imaging. − Recently, two main classes of HRIPs, namely intrinsic and nanocomposite HRIPs, have been developed . Nanocomposite HRIPs are inorganic–organic hybrid materials with organic polymer chains entangled with highly refractive inorganic nanoparticles, such as TiO 2 , ,,− ZrO 2 , ,, ZnS, , and graphene . Nanocomposite HRIPs gain an appreciation of high refractive indices (RIs > 1.8) but sometimes suffer from poor stability and processability because of the aggregation of nanoparticles .…”

“…14−16 Recently, two main classes of HRIPs, namely intrinsic and nanocomposite HRIPs, have been developed. 17 Nanocomposite HRIPs are inorganic−organic hybrid materials with organic polymer chains entangled with highly refractive inorganic nanoparticles, such as TiO 2 , 12,13,18−20 ZrO 2 , 9,21,22 ZnS, 6,23 and graphene. 24 Nanocomposite HRIPs gain an appreciation of high refractive indices (RIs > 1.8) but sometimes suffer from poor stability and processability because of the aggregation of nanoparticles.…”