Ultrahigh-resolution optical coherence tomography by broadband continuum generation from a photonic crystal fiber

Abstract

We have developed an ultrahigh-resolution optical coherence tomographic system in which broadband continuum generation from a photonic crystal fiber is used to produce high longitudinal resolution. Longitudinal resolution of 1.3-microm has been achieved in a biological tissue by use of continuum light from 800 to 1400 nm. The system employed a dynamic-focusing tracking method to maintain high lateral resolution over a large imaging depth. Subcellular imaging is demonstrated.

InAs Quantum Dots of Engineered Height for Fabrication of Broadband Superluminescent Diodes

“…A calculated axial resolution in air of 2.4µm (Haffouz et al, 2012) is expected from the SLDs with widest bandwidth and central wavelength around 106040nm. This lateral (axial) resolution is approaching that observed when using the state of the art but bulky and expensive femtosecond laser sources (Wang et al, 2003). To achieve finer axial resolution at central wavelength around 1060nm with the use of superluminescent diodes, one needs to further improve the design of the quantum dot and/or quantum well active region of the device, for allowing a wider bandwidth and higher output power, thus opening possibilities for OCT imaging with 1-2µm axial resolution range.…”

“…There are a myriad of choices in selecting such OCT light sources i) femtosecond or fiber lasers that are dispersed to produce super-continuum light and swept source lasers (Hartl et al, 2001;Wang et al, 2003), ii) thermal sources, and iii) superluminescent diodes (Sun et al, 1999;Liu et al, 2005;Lv et al, 2008;Haffouz et al, 2010). Although the reported OCT tomograms with the highest axial resolution (1.8m) were so far achieved in research laboratories with a photonic crystal fibre based source (Wang et al, 2003), superluminescent diodes are considerably lower in cost and complexity as well as being smaller in size, which makes them more attractive for mass production. Superluminescent diodes utilizing quantum-dots (QDs) in the active region are considered to be excellent candidates as light source for an OCT systems.…”

“…There are a myriad of choices in selecting such OCT light sources i) femtosecond or fiber lasers that are dispersed to produce super-continuum light and swept source lasers, and ii) superluminescent diodes. Highly non-linear air-silica microstructure fibers and photonic crystal fibers (PCFs) can generate an extremely broadband continuous light spectrum from the visible to the near infrared by use of low-energy femtosecond pulses (Wang et al, 2003;Hartl et al, 2011). Spectral bandwidth up to 372nm was achieved at 1.1µm central wavelength.…”

“…Although the reported OCT tomograms with the highest axial resolution (1.8m) were so far achieved in research laboratories with a photonic crystal fibre based source (Wang et al, 2003), superluminescent diodes are considerably lower in cost and complexity as well as being smaller in size, which makes them more attractive for mass production. Superluminescent diodes utilizing quantum-dots in the active region are considered to be an excellent candidate as a light source for an OCT system.…”

Extended bandwidth wavelength swept laser source for high resolution optical frequency domain imaging

“…Although a number of broadband light sources have been developed to improve axial resolution in time domain and SD-OCT [21][22][23][24], only a few broadband high-speed wavelength-swept light sources have been reported [25][26][27][28]. Semiconductor gain media can be easily incorporated into compact laser cavity designs and have been developed for many different spectral bands.…”