Current medical imaging technologies allow visualization of tissue anatomy in the human body at resolutions ranging from 100 micrometers to 1 millimeter. These technologies are generally not sensitive enough to detect early-stage tissue abnormalities associated with diseases such as cancer and atherosclerosis, which require micrometer-scale resolution. Here, optical coherence tomography was adapted to allow high-speed visualization of tissue in a living animal with a catheter-endoscope 1 millimeter in diameter. This method, referred to as "optical biopsy," was used to obtain cross-sectional images of the rabbit gastrointestinal and respiratory tracts at 10-micrometer resolution.

In Vivo Endoscopic Optical Biopsy with Optical Coherence Tomography

We report on advances in polymeric waveguide technologies developed worldwide for the telecom and datacom markets, and we describe in detail one such technology developed at AlliedSignal. Optical polymers are versatile materials that can be readily formed into planar single-mode, multimode, and microoptical waveguide structures ranging in dimensions from under a micrometer to several hundred micrometers. These materials can be thermoplastics, thermosets, or photopolymers, and the starting formulations are typically either polymers or oligomers in solution or liquid monomers. Transmission losses in polymers can be minimized, typically by halogenation, with state-of-the-art loss values being about 0.01 dB/cm at 840 nm and about 0.1 dB/cm at 1550 nm. A number of polymers have been shown to exhibit excellent environmental stability and have demonstrated capability in a variety of demanding applications. Waveguides can be formed by direct photolithography, reactive ion etching, laser ablation, molding, or embossing. Well-developed adhesion schemes permit the use of polymers on a wide range of rigid and flexible substrates. Integrated optical devices fabricated to date include numerous passive and active elements that achieve a variety of coupling, routing, filtering, and switching functions.

Advances in polymer integrated optics

The present disclosure relates to a semiconductor light emitting device, comprising: a plurality of semiconductor layers, including a first semiconductor layer having a first conductivity, a second semiconductor layer having a second conductivity different from the first conductivity, and an active layer interposed between the first semiconductor layer and the second semiconductor layer, generating light via electron-hole recombination; a first electrode, supplying either electrons or holes to the plurality of semiconductor layers; a second electrode, supplying, to the plurality of semiconductor layers, electrons if the holes are supplied by the first electrode, or holes if the electrons are supplied by the first electrode; a non-conductive distributed bragg reflector coupled to the plurality of semiconductor layers, reflecting the light from the active layer; and a first light-transmitting film coupled to the distributed bragg reflector from a side opposite to the plurality of semiconductor layers with respect to the non-conductive distributed bragg reflector, with the first light-transmitting film having a refractive index lower than an effective refractive index of the distributed bragg reflector.

Semiconductor Light Emitting Device

We demonstrate swept source OCT utilizing vertical-cavity surface emitting laser (VCSEL) technology for in vivo high speed retinal, anterior segment and full eye imaging. The MEMS tunable VCSEL enables long coherence length, adjustable spectral sweep range and adjustable high sweeping rate (50-580 kHz axial scan rate). These features enable integration of multiple ophthalmic applications into one instrument. The operating modes of the device include: ultrahigh speed, high resolution retinal imaging (up to 580 kHz); high speed, long depth range anterior segment imaging (100 kHz) and ultralong range full eye imaging (50 kHz). High speed imaging enables wide-field retinal scanning, while increased light penetration at 1060 nm enables visualization of choroidal vasculature. Comprehensive volumetric data sets of the anterior segment from the cornea to posterior crystalline lens surface are also shown. The adjustable VCSEL sweep range and rate make it possible to achieve an extremely long imaging depth range of ~50 mm, and to demonstrate the first in vivo 3D OCT imaging spanning the entire eye for non-contact measurement of intraocular distances including axial eye length. Swept source OCT with VCSEL technology may be attractive for next generation integrated ophthalmic OCT instruments.

Retinal, anterior segment and full eye imaging using ultrahigh speed swept source OCT with vertical-cavity surface emitting lasers.

Imaging speed is one of the most important parameters that define the performance of optical coherence tomography (OCT) systems. During the last two decades, OCT speed has increased by over three orders of magnitude. New developments in wavelength-swept lasers have repeatedly been crucial for this development. In this review, we discuss the historical evolution and current state of the art of high-speed OCT systems, with focus on wavelength swept light sources and swept source OCT systems.

High-speed OCT light sources and systems [Invited]

Organic electroluminescent diodes (OLED) were fabricated on a polymeric optical waveguide for use as an optical interconnector in data communication systems. The OLED were fabricated on an ITO sputtered polymer waveguide with a 45 degree mirror by vacuum deposition. The OLEDs, with an emission peak center at 520 nm consist of diamine derivative as a hole transporting layer and tris(8-hydroxyquinoline) aluminum (Alq3) as an emissive layer. We estimated the propagation losses of the waveguide to be 1.35 dB/cm at 520 nm. However, it decreases as increasing the wavelength of the light source and is estimated as 0.37 dB/cm at the wavelength of 614 nm. The optical pulse of more than 5 Mb/s has been obtained from the OLED with Alq3 and diamine derivative. We discuss the properties of the OLED for the light source for polymeric integrated devices.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

/pdf/organic-electroluminescent-diodes-as-a-light-source-for-2964r7w9k8.pdf

Organic electroluminescent diodes as a light source for polymeric integrated devices

Buried channel optical waveguides were fabricated from fluorinated
polyimides. They operated in single mode and showed an optical loss
of less than 0.3 and 0.7 dB/cm for TE and TM polarizations,
respectively, at a wavelength of 1.3 μm. Moreover, these
waveguides had high heat and moisture resistance; the optical loss did
not significantly change after heating at 380 °C for 1 h or
after exposure to 85% relative humidity at 85 °C for over 200
h.

Single-mode optical waveguides fabricated from fluorinated polyimides.

We describe modulation characteristics of organic light-emitting diodes (OLEDs) using 8-hydroxyquinoline aluminum (Alq3) as an electro-optical conversion device for polymeric integrated devices. Optical pulses of more than 100 MHz were created by directly modulating a yellow emitting OLED with rubrene doped in Alq3 as an emissive layer which has the advantages of low propagation loss in the polymer waveguide and high emission intensity. We demonstrate that the OLEDs can be applied to fields of optical communication as electro-optical conversion devices for transmitting the signals of moving images.

https://iopscience.iop.org/article/10.1143/JJAP.41.2746/pdf

Transient Properties of Organic Electroluminescent Diode Using 8-Hydroxyquinoline Aluminum Doped with Rubrene as an Electro-Optical Conversion Device for Polymeric Integrated Devices.

A new light source for swept-source optical coherence tomography (SS-OCT) is presented, namely, an external-cavity LD equipped with a KTN electro-optic deflector. The KTN deflector is unique in being very fast and simultaneously providing an appreciable deflection caused by injected carriers. Being free from mechanical resonance, the 1.3 µm laser exhibits a scanning range of almost 80 nm up to 200 kHz with a ±400 V deflector driving voltage. Preliminary SS-OCT images of a human fingernail and finger skin have been obtained using the swept light source.

200 kHz swept light source equipped with KTN deflector for optical coherence tomography

High temperature x-ray diffractometry (HT-XRD) and differential scanning calorimetry (DSC) measurements confirm that two kinds of structural phase transitions exist in LaGaO3. One is the first order transition from the orthorhombic to the rhombohedral structure at ∼150 °C. The other is the second order transition from the rhombohedral to the monoclinic structure from ∼750 °C to ∼1000 °C.

Kobayashi Junya

Papers

Organic electroluminescent diodes as a light source for polymeric integrated devices

Single-mode optical waveguides fabricated from fluorinated polyimides.

Transient Properties of Organic Electroluminescent Diode Using 8-Hydroxyquinoline Aluminum Doped with Rubrene as an Electro-Optical Conversion Device for Polymeric Integrated Devices.

200 kHz swept light source equipped with KTN deflector for optical coherence tomography

Structural analysis of lanthanum gallate