In this paper we demonstrate a preliminary work done on employing antimony telluride (Sb<sub>2</sub>Te<sub>3</sub>) topological insulator as a saturable absorber for Yb-doped fiber lasers. The material was deposited onto a side-polished fiber by means of a pulsed magnetron sputtering technique. Fabricated absorber was implemented in an all-normal dispersion cavity and allowed for self-starting dissipative soliton generation. The laser emitted stable pulse train at a repetition rate of 17.07 MHz with 4.25 nm broad output spectrum centered around 1039.4 nm. Average output power amounted to 0.54 mW with 32 pJ pulse energy.
We demonstrate the usage of a saturable absorber material - antimony telluride (Sb<sub>2</sub>Te<sub>3</sub>) for efficient mode-locking of a Thulium-doped fiber laser. The Sb<sub>2</sub>Te<sub>3</sub> layers were obtained by mechanical exfoliation and transferred onto the fiber ferrule. The all-fiber laser was capable of generating optical solitons with the full width at half-maximum of 4.5 nm centered at 1945 nm, with 39.5 MHz repetition rate and more than 60 dB signal to noise ratio. The pulse energy of the generated 890 fs pulses was at the level of 30 pJ. Our experiment showed that Sb<sub>2</sub>Te<sub>3</sub> saturable absorbers are suitable for the operation in 2 μm bandwidth.
In this work, we demonstrate a high-pulse energy, fiber-based chirped pulse amplification (CPA) setup utilizing Er- and Er/Yb-doped fibers, operating at 1555 nm central wavelength. The integrated pulse-picker allows to reduce the repetition frequency down to the kHz-range, which enables generation of sub-picosecond pulses with energies above 2 μJ and pulse peak power exceeding 1 MW. The system utilizes an Er/Yb co-doped large mode area fiber in the final amplification stage. Thanks to the used mode-field adaptors, the setup is almost fully fiberized, except the bulk grating pulse compressor.
We present an Er-doped fiber mode-locked laser based on an evanescent field interaction with the Sb2Te3 topological insulator. The saturable absorber (SA) consist of a bulk piece of Sb2Te3 material placed on the side-polished fiber in the presence of UV curable polymer. The measured SA optical parameters like: linear absorption, modulation depth and non-saturable loses were of 50%, 6% and 43%, respectively. The SA was spliced into the ring laser cavities characterized by the all-anomalous, all-normal and balanced dispersion. Such laser resonators allowed for optical solitons, dissipative solitons and Gaussian pulses generation with 3dB bandwidth of 8.5 nm, 37 nm and 17 nm, respectively.
We present first to our knowledge self-starting graphene-chitosan based ultrafast fiber laser setup. Graphene-chitosan composite placed between two fibres connectors is saturable absorber in demonstrated setup and is responsible for modelocking operation. Laser is built with polarization maintaining fibres which grants self-start feature. Laser produces ~300 fs soliton pulses centered at 1566 nm with 10 nm FHWM optical bandwidth. Time bandwidth product of demonstrated laser is 0.37. Repetition rate of 42 MHz and average output power of 1.2 mw corresponds to pulse energy and peak power of 20 pJ and 62 W, respectively. As an active media in laser Erbium-doper fiber was used. Presented setup proves graphene is novel promising material for ultrafast lasers production at worldwide scale.
In this work, femtosecond pulse generation in Er-doped fiber laser using graphene oxide (GO) paper based saturable absorber (SA) is presented. The article includes the characterization of optical properties of prepared SA material and detailed description of the laser performance. Stable mode-locking operation was achieved, with 515 fs soliton pulses centered at 1559 nm. The GO paper SA is characterized by 5.4% modulation depth and 155 MW/cm<sup>2</sup> of saturation intensity. The nearly wavelength-independent linear absorption combined with straightforward fabrication process make it a suitable material for application as a SA in low-power mode-locked fiber lasers operating in various spectral ranges.
Recent advances in the development of compact sensors based on mid-infrared continuous wave (CW), thermoelectrically
cooled (TEC) and room temperature operated quantum cascade lasers (QCLs) for the detection, quantification and
monitoring of trace gas species and their applications in environmental and industrial process analysis will be reported. These
sensors employ a 2f wavelength modulation (WM) technique based on quartz enhanced photoacoustic spectroscopy
(QEPAS) that achieves detection sensitivity at the ppb and sub ppb concentration levels. The merits of QEPAS include an
ultra-compact, rugged sensing module, with wide dynamic range and immunity to environmental acoustic noise. QCLs are
convenient QEPAS excitation sources that permit the targeting of strong fundamental rotational-vibrational transitions which
are one to two orders of magnitude more intense in the mid-infrared than overtone transitions in the near infrared spectral
The development of high energy and high power lasers based on solid state technology is mostly limited by thermal effects that occur inside the laser cavity under high heat loads and intensities. The thermo-optical effects emerging inside cavity mirrors, output couplers and windows can significantly degrade beam quality of such lasers. The knowledge on transient thermal effects occurring inside bulk laser elements exposed on laser intensities of several dozens of kW/cm2 is of special interest for some specific applications (e.g. heat capacity lasers). The goal of this paper were theoretical analysis and experimental verification of these effects. Tips for best materials choice for cavity mirrors, laser windows and output couplers were shown. Simple theoretical thermo-optical model was presented. The special laboratory setup allowing simultaneous registration of thermo-optical effects applying shearing interferometer and wavefront sensor (Shack-Hartmann test) was elaborated. The non-stationary and stationary thermo-optical effects emerging inside tested mirrors can be observed, be measured and resolved as result of surface absorption in coating layers and volume absorption in the material. The resolution of measurements: less than 0.1 K and thermally induced optical power of about 0.1 D were demonstrated.
The most important limitations in development of high energy and high power lasers based on solid state technology are
thermal effects occurring under high intensity and high heat loads. The thermo-optical effects occurring inside output
couplers, folding mirrors, output windows can significantly diminish the beam quality of high power lasers and therefore
have to be investigated. The knowledge on transient thermal effects occurring inside bulk laser elements exposed on
laser intensities of several dozens of kW/cm<sup>2</sup> is of special interest for some specific applications (e.g. heat capacity
lasers). The aims of work were theoretical analysis of those effects occurring inside the laser mirrors and its experimental
verification. The hints for choice of the best materials (from the point of view of thermal limitations) for laser windows
and output couplers were pointed out. The special laboratory setup enabling simultaneous registration of thermo-optical
effects applying shearing interferometry and wavefront sensing by means of Shack-Hartmann test was worked out. The
transient as well as averaged in time thermal-optical effects occurring inside the volume of examined element as a result
of surface absorption in the coatings and bulk absorption in the material can be resolved and measured. The resolution of
measurements: less than 0.1 K temperature difference and thermally induced optical power of about 0.1 D were