Track topics on Twitter Track topics that are important to you
A transmissive optical system of a three-dimensional (3D) printer using the laser metal deposition (LMD) technique with a metal powder is proposed here, together with its design method. An f-number of the focused laser beam emitted from the optical system should be large enough for the laser beam not to be absorbed or reflected by the metal powder injection nozzle. On the other hand, owing to the Lagrange-Helmholtz relation, the f-number should be small enough to form a minute laser spot diameter for high-resolution building. A temperature rise induced by the high-power laser may cause damage or a thermal lens effect on the optical system, which can be reduced by using lenses having plano-surfaces contacting thermally with holders. A formula of the relationship of the thermal lens effect with an f-number of each lens is derived to determine the lens specifications. A formula of longitudinal spherical aberration (LSA) of these lenses is also derived, and the total LSA is shown to be able to be zero with an acceptable f-number of the focused laser beam. The prototype LMD 3D printer with 6 kW laser is fabricated and shows favorable properties, such as a minimum building width of 0.3 mm and a building speed of over 500 cc/h.
This article was published in the following journal.
Name: Applied optics
Optical technologies in the LWIR spectrum (7-14 mm) offer important advantages for high resolution thermal imaging in near, or complete darkness, which has been extensively utilized in the defense sec...
To demonstrate the value of the laser-scanning optical-resolution (LSOR)-photoacoustic (PA) microscopy (PAM) system and the conventional multimodal imaging techniques in the evaluation of laser-induce...
This paper describes the optical design of the High Resolution Imaging Channel (HRIC), which is part of the spectrometers and imagers for the Mercury Planetary Orbiter BepiColombo Integrated Observato...
In the reservoir computing (RC) system based on delay line structure, the dynamical reservoir has short-term memory capability and can map instantaneous time signals to a high-dimensional space, so th...
We demonstrate optical unlocking of a cavity resonance in a mid-infrared (MIR) quantum cascade laser (QCL) cavity ring-down spectrometer using a low-power multimode near-infrared (NIR) laser diode. A ...
Imaging of retinal morphological changes with time secondary to laser treatment as assessed with high definition optical coherence tomography (OCT). Furthermore changes in retinal function...
The purpose of this study is to monitor the performance and compare the metal ion release of two bearing combinations, ceramic-on-metal and metal-on-metal in the treatment of patients with...
The primary objective of this investigation is to evaluate the clinical and radiographic outcomes of the ASR™-XL Acetabular Cup System compared to the Pinnacle™ Acetabular Cup with a 2...
Traditional biopsy requires the removal, fixation, and staining of tissues from the human body. Its procedure is invasive and painful. Non-invasive in vivo optical biopsy is thus required,...
This study is in response to the Food and Drug Administration (FDA) call to all manufacturers with 510(k) clearance for metal-on-metal (MoM) total hip arthroplasty (THA) devices to conduct...
A technique utilizing a laser coupled to a catheter which is used in the dilatation of occluded blood vessels. This includes laser thermal angioplasty where the laser energy heats up a metal tip, and direct laser angioplasty where the laser energy directly ablates the occlusion. One form of the latter approach uses an EXCIMER LASER which creates microscopically precise cuts without thermal injury. When laser angioplasty is performed in combination with balloon angioplasty it is called laser-assisted balloon angioplasty (ANGIOPLASTY, BALLOON, LASER-ASSISTED).
The plan and delineation of dental prostheses in general or a specific dental prosthesis. It does not include DENTURE DESIGN. The framework usually consists of metal.
The use of light interaction (scattering, absorption, and fluorescence) with biological tissue to obtain morphologically based information. It includes measuring inherent tissue optical properties such as scattering, absorption, and autofluorescence; or optical properties of exogenous targeted fluorescent molecular probes such as those used in optical MOLECULAR IMAGING, or nontargeted optical CONTRAST AGENTS.
Techniques using laser energy in combination with a balloon catheter to perform angioplasty. These procedures can take several forms including: 1, laser fiber delivering the energy while the inflated balloon centers the fiber and occludes the blood flow; 2, balloon angioplasty immediately following laser angioplasty; or 3, laser energy transmitted through angioplasty balloons that contain an internal fiber.
Somatosensory evoked potentials generated through the application of HEAT to the SKIN with a LASER. They are often used clinically to assess the function of the central nociceptive system and in diagnosing NOCICEPTIVE PAIN.