All-fiber Frequency Comb Employing a Single Walled Carbon Nanotube Saturable Absorber for Optical Frequency Metrology in Near Infrared

All-fiber Frequency Comb Employing a Single Walled Carbon Nanotube Saturable Absorber for Optical Frequency Metrology in Near Infrared
Author: Jinkang Lim
Publisher:
Total Pages:
Release: 2011
Genre:
ISBN:

Optical frequency combs produced by mode-locked fiber lasers are useful tools for high precision frequency metrology and molecular spectroscopy in a robust and portable format. We have specifically investigated erbium doped fiber mode-locked lasers that use single-walled carbon nanotubes as a saturable absorber. We have, for the first time, developed and phase- stabilized a carbon nanotube fiber laser (CNFL) frequency comb. The carbon nanotube saturable absorber, which was fabricated using an optically driven deposition method, permits a high repetition frequency (>150 MHz) since an optical nonlinearity of fibers is not used for mode-locking. The CNFL comb combined with a parabolic pulse erbium doped fiber amplifier (EDFA) has shown a compact, robust, and cost-effective supercontinuum source. The amplified pulse from the parabolic pulse EDFA was compressed with a hollow-core photonic bandgap fiber, which produced a wave-breaking-free pulse with an all-fiber set-up. The stabilized comb has demonstrated a fractional instability of 1.2 ©--10[superscript]-11 at 1 sec averaging time, the reference-limited instability. We have performed optical frequency metrology with the CNFL comb and have measured an optical frequency, P(13) which is a molecular overtone transition of C2H2. The measured frequency has shown a good agreement with the known value within an uncertainty of 10 kHz. In order to extend the application of the CNFL comb such as multi-heterodyne dual comb spectroscopy, we have investigated the noise of the CNFL comb and particularly, the broad carrier envelope offset frequency (f[subscript]0) linewidth of the CNFL comb. The primary noise source is shown to be white amplitude noise on the oscillator pump laser combined with the sensitivity of the mode-locked laser to pump power fluctuations. The control bandwidth of f[subscipt]0 was limited by the response dynamics of the CNFL comb. The significant reduction of comb noise has been observed by implementing a phase-lead compensation to extend control bandwidth of the comb and by reducing the pump relative intensity noise simultaneously. Therefore the f[subscipt]0 linewidth has been narrower from 850 kHz to 220 kHz. The integrated phase noise for the f[subscipt]0 lock is 1.6 radians from 100 Hz to 102 kHz.

Frequency Combs for Spectroscopy and Optical Metrology

Frequency Combs for Spectroscopy and Optical Metrology
Author: Md Imrul Kayes
Publisher:
Total Pages:
Release: 2019
Genre:
ISBN:

"Since their inception, optical frequency combs have created novel avenues for numerous applications such as molecular spectroscopy, atomic clocks, coherent communications, and microwave photonics. The future of frequency combs lies in exploring different comb generation technique, customized for specific applications. This thesis explores the synthesis of novel optical frequency combs in the near infrared wavelength region and the applications of such combs in the field of high-resolution spectroscopy and precise distance measurement. First, the generation of an electro-optic frequency comb with adjustable central wavelength and frequency spacing is experimentally demonstrated. This frequency comb is sourced from a single mode Brillouin fiber laser having an ultra-narrow linewidth that improves the overall phase noise performance of the comb spectral lines. A combined effect of electro-optic modulation, dispersion compensation, and fiber nonlinearity convert the continuous wave laser into a wideband optical frequency comb encompassing the C-band. Next, this frequency comb is used for a high-resolution distance measurement system that operates from the repetition rate modulation of the comb signal. The repetition frequency of the electro-optic comb is adjustable with a high dynamic range. Such broad tunablity of the repetition rate facilitates the measurement of distances with μm level precision. Such a system is also capable of motion tracking thanks to the rapid scan rate of the repetition frequency. Next, the application of electro-optic combs in high-resolution Fourier transform spectroscopy is demonstrated by measuring absorption lines of a chemical sample at 1.55 μm. The pulse train from a frequency comb, subject to a repetition rate modulation, stores the spectral response of a sample when sent to a length imbalanced interferometer. Such a system is equivalent to a dual-comb spectrometer but without the need for a complex phase matching mechanism. Finally, a novel laser resonator is developed for high-resolution dual-comb spectroscopy at 1.9 μm. This resonator supports two counter-propagating laser oscillations sharing a common cavity which relaxes the phase matching requirement for dual-comb spectroscopy. A proof-of-concept experiment demonstrated the measurement of absorption lines of ambient water vapor with a 100 MHz resolution. This approach holds great promise for dual-comb spectroscopy in the mid-infrared region where many chemicals have strong fundamental transitions"--

Direct Fiber Laser Frequency Comb Stabilization Via Single Tooth Saturated Absorption Spectroscopy in Hollow-core Fiber

Direct Fiber Laser Frequency Comb Stabilization Via Single Tooth Saturated Absorption Spectroscopy in Hollow-core Fiber
Author: Shun Wu
Publisher:
Total Pages:
Release: 2014
Genre:
ISBN:

Portable frequency references are crucial for many practical on-site applications, for example, the Global Position System (GPS) navigation, optical communications, and remote sensing. Fiber laser optical frequency combs are a strong candidate for portable reference systems. However, the conventional way of locking the comb repetition rate, f[subscript]r[subscript]e[subscript]p, to an RF reference leads to large multiplied RF instabilities in the optical frequency domain. By stabilizing a comb directly to an optical reference, the comb stability can potentially be enhanced by four orders of magnitude. The main goal of this thesis is to develop techniques for directly referencing optical frequency combs to optical references toward an all-fiber geometry. A big challenge for direct fiber comb spectroscopy is the low comb power. With an 89 MHz fiber ring laser, we are able to optically amplify a single comb tooth from nW to mW (by a factor of 106) by building multiple filtering and amplification stages, while preserving the comb signal-to-noise ratio. This amplified comb tooth is directly stabilized to an optical transition of acetylene at ~ 1539.4 nm via a saturated absorption technique, while the carrier-envelope offset frequency, f0, is locked to an RF reference. The comb stability is studied by comparing to a single wavelength (or CW) reference at 1532.8 nm. Our result shows a short term instability of 6 x10−12 at 100 ms gate time, which is over an order of magnitude better than that of a GPS-disciplined Rb clock. This implies that our optically-referenced comb is a suitable candidate for a high precision portable reference. In addition, the direct comb spectroscopy technique we have developed opens many new possibilities in precision spectroscopy for low power, low repetition rate fiber lasers. For single tooth isolation, a novel cross-VIPA (cross-virtually imaged phase array) spectrometer is proposed, with a high spectral resolution of 730 MHz based on our simulations. In addition, the noise dynamics for a free space Cr:forsterite-laser-based frequency comb are explored, to explain the significant f0 linewidth narrowing with knife insertion into the intracavity beam. A theoretical model is used to interpret this f0 narrowing phenomenon, but some unanswered questions still remain.

Self-referenced 1.5 [mu]m Fiber Frequency Combs at GHz Repetition Rates

Self-referenced 1.5 [mu]m Fiber Frequency Combs at GHz Repetition Rates
Author: David Chao (Ph. D.)
Publisher:
Total Pages: 142
Release: 2012
Genre:
ISBN:

Tremendous advances in recent years to the optical frequency comb, particularly frequency combs deriving from solid-state and fiber architectures, have enabled a host of important new applications to emerge - applications which include optical arbitrary waveform generation (OAWG), high-speed photonic analog-to-digital conversion (EPIC), space exploration (Astro- Comb) as well as precision spectroscopy and optical clocks. Fiber-based frequency combs have increasingly become attractive alternatives to solid-state systems due to their compact size and robust operation and have recently demonstrated performance comparable to their more traditional counterparts. One area for improvement, however, is in the repetition rate of such systems, as fiber frequency combs based on Ytterbium (Yb) and Erbium (Er) technologies currently only operate with repetition rates =/

Solubilization and Dispersion of Carbon Nanotubes

Solubilization and Dispersion of Carbon Nanotubes
Author: Oxana Vasilievna Kharissova
Publisher: Springer
Total Pages: 258
Release: 2017-09-01
Genre: Technology & Engineering
ISBN: 3319629506

This book describes a series of contemporary techniques and their combinations used for CNTs solubilization, from physical to chemical and biological, applying inorganic and organic compounds, as well as some metal complexes. In some cases, successive steps can be applied, for instance the use of low and high-weight surfactants, or mineral acid treatment for creation of –OH and –COOH groups and their further interaction with organic molecules. Each discussed method leads to an improvement of CNT solubility, frequently a considerable one. The formed dispersions can be stable for long periods of time, from several weeks to some months, and they sometimes even remain stable after centrifugation. Several special studies have been carried out in the areas of influence of solvent and light on CNTs dispersibility, combinations and abilities of surfactants, CNT cytotoxicity, etc. Applications of solubilized CNTs are discussed in this book as well.

Two-dimensional Materials

Two-dimensional Materials
Author: Pramoda Kumar Nayak
Publisher: BoD – Books on Demand
Total Pages: 282
Release: 2016-08-31
Genre: Technology & Engineering
ISBN: 9535125540

There are only a few discoveries and new technologies in materials science that have the potential to dramatically alter and revolutionize our material world. Discovery of two-dimensional (2D) materials, the thinnest form of materials to ever occur in nature, is one of them. After isolation of graphene from graphite in 2004, a whole other class of atomically thin materials, dominated by surface effects and showing completely unexpected and extraordinary properties, has been created. This book provides a comprehensive view and state-of-the-art knowledge about 2D materials such as graphene, hexagonal boron nitride (h-BN), transition metal dichalcogenides (TMD) and so on. It consists of 11 chapters contributed by a team of experts in this exciting field and provides latest synthesis techniques of 2D materials, characterization and their potential applications in energy conservation, electronics, optoelectronics and biotechnology.

Vertical External Cavity Surface Emitting Lasers

Vertical External Cavity Surface Emitting Lasers
Author: Michael Jetter
Publisher: John Wiley & Sons
Total Pages: 584
Release: 2021-09-16
Genre: Technology & Engineering
ISBN: 3527807977

Vertical External Cavity Surface Emitting Lasers Provides comprehensive coverage of the advancement of vertical-external-cavity surface-emitting lasers Vertical-external-cavity surface-emitting lasers (VECSELs) emit coherent light from the infrared to the visible spectral range with high power output. Recent years have seen new device developments – such as the mode-locked integrated (MIXSEL) and the membrane external-cavity surface emitting laser (MECSEL) – expand the application of VECSELs to include laser cooling, spectroscopy, telecommunications, biophotonics, and laser-based displays and projectors. In Vertical External Cavity Surface Emitting Lasers: VECSEL Technology and Applications, leading international research groups provide a comprehensive, fully up-to-date account of all fundamental and technological aspects of vertical external cavity surface emitting lasers. This unique book reviews the physics and technology of optically-pumped disk lasers and discusses the latest developments of VECSEL devices in different wavelength ranges. Topics include OP-VECSEL physics, continuous wave (CW) lasers, frequency doubling, carrier dynamics in SESAMs, and characterization of nonlinear lensing in VECSEL gain samples. This authoritative volume: Summarizes new concepts of DBR-free and MECSEL lasers for the first time Covers the mode-locking concept and its application Provides an overview of the emerging concept of self-mode locking Describes the development of next-generation OPS laser products Vertical External Cavity Surface Emitting Lasers: VECSEL Technology and Applications is an invaluable resource for laser specialists, semiconductor physicists, optical industry professionals, spectroscopists, telecommunications engineers and industrial physicists.

Design and Applications of Kerr Frequency Combs

Design and Applications of Kerr Frequency Combs
Author: Tristan Melton
Publisher:
Total Pages: 0
Release: 2023
Genre:
ISBN:

Optical frequency combs have become a major source of innovation in a wide array of fields such as metrology, ultrafast optics, and light-matter interactions. Specifically, Kerr frequency combs have risen to the forefront of comb sources in applications requiring small size, light weight, and relatively low power consumption (SWaP). The design and generation of Kerr frequency combs at 1-micron and their application in frequency-domain optical coherence tomography (FD-OCT) and microwave generation are explored. Microresonators are designed in a silicon nitride platform to generate octave-spanning comb states. Then, various comb states are generated at this wavelength to explore comb dynamics, including stabilization. Platicon combs are also examined at 1600-nm. Finally, 1-μm Kerr frequency comb FD-OCT with comparable image quality to that of a traditional superluminescent diode FD-OCT is demonstrated with an effective axial resolution that approaches the theoretical limit.