Miniature Optical System Research Articles

Miniature optical force levitation system

Optical levitation technology is a new levitation technology for trapping micro/nano-particles. By taking advantage of the mechanical effect of light, it has the characteristics of non-contact and high sensitivity. However, the traditional optical levitation system is large in volume, complex in adjustment, and greatly affected by the external environment. Herein, a miniature optical levitation system based on a laser diode, miniature lenses, and a micro-electro-mechanical system (MEMS) particles cavity is proposed. First, we analyze the output spot characteristics of the laser diode. Being compared the characteristics of different kinds of laser diodes, the type, wavelength, and power of diodes in the levitation system are determined. Then, the micro-particles cavity is fabricated based on the MEMS process. The MEMS process is widely used in the manufacturing of micro-electronic devices because of its advantages of small size, high precision, and easy mass production. The particle cavity processed in this way can not only ensure the advantage of small volume, but also possesses high processing repeatability. The volume of the entire package including the light source, focusing lenses, and MEMS cavity is just Φ 10 mm×33 mm, which is the smallest optical levitation system reported, to the best of our knowledge. After the entire levitation system is designed and set up, one silica particle of 10 µm diameter is stably trapped in the atmospheric environment. Finally, the micro-displacement and vibration signal are detected by a four-quadrant photoelectric detector to evaluate the stiffness of the optical levitation system.

A Miniature Optical Force Dual-Axis Accelerometer Based on Laser Diodes and Small Particles Cavities.

In recent years, the optical accelerometer based on the optical trapping force effect has gradually attracted the attention of researchers for its high sensitivity and high measurement accuracy. However, due to its large size and the complexity of optical path adjustment, the optical force accelerometers reported are only suitable for the laboratory environment up to now. In this paper, a miniature optical force dual-axis accelerometer based on the miniature optical system and a particles cavity which is prepared by Micro-Electro-Mechanical Systems (MEMS) technology is proposed. The overall system of the miniature optical levitation including the miniature optical system and MEMS particles cavity is a cylindrical structure with a diameter of about 10 mm and a height of 33 mm (Φ 10 mm × 33 mm). Moreover, the size of this accelerometer is 200 mm × 100 mm × 100 mm. Due to the selected light source being a laser diode light source with elliptical distribution, it is sensitive to the external acceleration in both the long axis and the short axis. This accelerometer achieves a measurement range of ±0.17 g–±0.26 g and measurement resolution of 0.49 mg and 1.88 mg. The result shows that the short-term zero-bias stability of the two orthogonal axes of the optical force accelerometer is 4.4 mg and 9.2 mg, respectively. The main conclusion that can be drawn is that this optical force accelerometer could provide an effective solution for measuring acceleration with an optical force effect for compact engineering devices.

Miniature all-optical flexible forward-viewing photoacoustic endoscopy probe for surgical guidance.

A miniature flexible photoacoustic endoscopy probe that provides high-resolution 3D images of vascular structures in the forward-viewing configuration is described. A planar Fabry–Perot ultrasound sensor with a bandwidth of 53 MHz located at the tip of the probe is interrogated via a flexible fiber bundle and a miniature optical relay system to realize an all-optical probe measuring 7.4 mm in outer diameter at the tip. This approach to photoacoustic endoscopy offers advantages over previous piezoelectric based distal-end scanning probes. These include a forward-viewing configuration in widefield photoacoustic tomography mode, finer spatial sampling (87 µm spatial sampling interval), and wider detection bandwidth (53 MHz) than has been achievable with conventional ultrasound detection technology and an all-optical passive imaging head for safe endoscopic use.

Robust subwavelength focusing of surface plasmons on graphene

Graphene plays a substantial role in nano-scale optical engineering and miniature information signal processing systems gradually. In this letter, we propose a pipe-like substrate scheme to achieve the properly designed inhomogeneous, nonuniform conductivity distribution on a single sheet of graphene. The transverse-magnetic surface plasmon polariton wave supported by graphene will oscillate like water running in an inclined pipe and focus onto one point in a deep-subwavelength scale in the graphene sheet. Importantly, we find that this focusing behavior is robust and insensitive to the variance of background Fermi energy and incident frequency based on the analytic analysis. We verify our scheme by exploiting Hamiltonian optics and numerical calculation. This nano-scale optical manipulation will lead to the development of miniature optical system integration on a 1-atom-thick structure.

全天时星敏感器光学系统参量选择与光学设计

detecting a 4.5 magnitude star in the observation height of 10 km, the radiance of stars between 600~1100 nm was analyzed, the radiance of sky background and the optical transmission of atmosphere were calculated by using modtran. when the threshold of snr is 5, typical parameters are selected. with a plane mirror and a silicon material sphere lens, a lighter miniature optical system was designed. the result shows that the optical system spot shape approaches a circle between 600~1100 nm of full field of view, modulation transfer function approaches perfection and have outstanding image of quality. the ground-based daytime and nighttime detection snr of the star tracter is calculated and the detection ability limit is estimated in the threshold 5 of snr, which is 2.5 stellar magnitude g star in daytime on the ground and 6 at night. © 2016, science press. all right reserved.

A Miniature Optical Neuronavigation System for CT-Guided Stereotaxy

Background and Objective: Neuronavigation devices have progressed over the past 2 decades, but logistical limitations remain for many stereotactic procedures. We describe our technique and accuracy for a novel miniature optical tracking system which overcomes these limitations. Method: The minioptical tracking system uses a miniature video camera mounted on a rigid cannula to determine cannula location and orientation relative to a patient-attached sticker containing reference markers. A CT scan is used to register these markers to the anatomy and a user-selected target. A computer displays the cannula guidance information to the target. Bench testing was performed on 225 targets in a custom test phantom and additional testing was performed on 20 small targets in an anthropomorphic head phantom to determine the practical accuracy and workflow. Results: The phantom study demonstrated that 3-D navigation accuracy is 1.41 ± 0.53 mm. There was a 100% head phantom study success rate for the 20 small targets. Conclusions: The resulting accuracy data demonstrated good correlation with the CT data, and the clinical simulation workflow indicated its potential usefulness for common neurosurgical applications. Furthermore, this small-footprint tracking technology does not experience the traditional environmentally induced issues or the requirement of pin-based head fixation, allowing for use in the neurointensive care unit and the emergency department.

Minioptical Navigation System for CT-Guided Percutaneous Liver Procedures

Purpose: To evaluate a new miniature optical navigation system for CT-guided liver interventions. Material and Methods: A two-center, prospective study was performed with four interventional radiologists. A total of 20 patients had CT-guided liver biopsy or ablation interventions utilizing the CT-Guide? navigation system (ActiViews Inc., Wakefield, MA) between July 2011 and December 2011. The navigation system consists of a self-adhesive patientsticker printed with coincident colored and radio-opaque reference markers, a miniature disposable video camera that clips on and off an interventional instrument, and software loaded on a computer to display the navigation information. The primary end point was the frequency of a satisfactory instrument position for the intended intervention. Results: The cohort consisted of 13 males and 7 females with an average age of 63.1 years (range of 38 to 80). Most of the patients, 70%, underwent CT-guided liver biopsy while the remainder had CT-guided ablation therapy. The average lesion size was 3.1 cm (range of 1.1 - 6.9 cm). All of the interventions, regardless of lesion size, met the primary end point of satisfactory instrument positioning. There were no device-related or unexpected adverse events recorded. Only one patient had a mild adverse event and it resolved without intervention. Conclusions: This study demonstrated the safety and effectiveness of the CT-Guide? navigation system for CT-guided liver interventions, for both biopsies and ablations. The targeting success rate for a satisfactory intervention was 100% with the system.

A Phototransistor-Based High-Sensitivity Biosensing System Using 650-nm Light

A miniature optical biosensing system based on a PMOS phototransistor and absorption photometry is proposed. The phototransistor was manufactured in a standard 0.35-mum CMOS process, and it exhibited a responsivity higher than 1000 A/W for 650-nm light. For biochemical applications, the TMB/H2O2/HRP method was adopted as a useful basis in our system. A sample volume of only 10 mul was required to be dropped on the slide above the phototransistor. Experimental results demonstrated that a high sensitivity of 2.5 muA/pM was achieved, and the minimum HRP concentration successfully detected was 2.7 pM. This detection limit is three orders of magnitude better than that of a lately reported silicon biosensor, and is even comparable to that of a commercial spectrophotometer.

Abstract 2055: Non-Invasive Measurements for Predicting Duration of Untreated Cardiac Arrest

Objective. Initial chest compression rather than defibrillation has evolved as the initial intervention when the duration of untreated cardiac arrest exceeds 4 min. Accordingly, we sought methods by which the duration of untreated cardiac arrest could be reliably estimated and communicated to the rescuer. Both AMSA (the amplitude spectrum area) together with measurements of tissue PCO 2 in the buccal mucosa (P BU CO2) were investigated. We hypothesized that decreases in AMSA, reflecting reduced myocardial electrical function, and increases in P BU CO 2 , reflecting the severity of anaerobic metabolism, would fulfil this need. Materials and Methods. In 9 domestic male pigs weighing 41 ± 2 kg, ventricular fibrillation (VF) was electrically induced and untreated for 15 min. AMSA was analyzed by fast Fourier transform from the ECG signal obtained through conventional precordial electrodes. P BU CO 2 was continuously measured utilizing a miniature optical sensor system (CO 2 ABG Module, Vasomed, Minneapolis, MN) applied non-invasively on to the buccal mucosa. Results . After 3 min of untreated VF, the AMSA value decreased significantly (p < 0.01, Figure ). P BU CO 2 progressively increased, exceeding threshold levels after 4 min. AMSA and P BU CO 2 were remarkably highly correlated with the durations of untreated cardiac arrest (r = 0.99 and r = 0.92, p < 0.0001) and with each other (r = −0.95, p < 0.0001). Conclusion. AMSA and P BU CO 2 both represent methods by which the duration of untreated cardiac arrest may be identified such as to prompt rescuer to immediately defibrillate or begin chest compression.

Microchip optical parametric oscillators

The frequency-doubled output of a high-power passively Q-switched Nd:YAG microchip laser has been used to pump a KTP doubly resonant miniature monolithic Fabry-Perot (microchip) optical parametric oscillator (OPO). The OPO operated with 20% conversion efficiency, generating 8.4 μJ of 1.064-μm radiation in 600-ps pulses, with excellent mode quality and pulse-to-pulse stability. This is the most compact OPO system yet demonstrated, generating the shortest pulses reported for an OPO pumped with Q-switched pulses. This technology makes it possible to obtain miniature optical system operating at any wavelength throughout the near IR, visible, and UV.