Raman sensing and microscopy are amongst the most specific optical technologies to identify chemical compounds of unknown samples, enable label-free biomedical imaging with molecular contrast. However, high cost complexity, low speed, incomplete spectral information provided by current technology major challenges preventing more widespread application systems. To overcome these limitations, we developed a new method for stimulated spectroscopy using continuous wave (CW), rapidly wavelength...

Surgical microscopes are vital tools for ophthalmic surgeons. The recent development of an integrated OCT system the first time allows to look at tissue features below surface. Hence, these systems can drastically improve quality and reduce risk surgical interventions. However, current commercial OCT-enhanced provide only one additional cross sectional view standard microscope image feature a low update rate. To present volumetric data high rate, much faster than ones applied in today's need...

We present a new 1060 nm Fourier domain mode locked laser (FDML laser) with record 143 sweep bandwidth at 2∙ 417 kHz = 834 and 120 1.67 MHz, respectively. show that not only the alone, but also shape of spectrum is critical for resulting axial resolution, because specific wavelength-dependent absorption vitreous. The theoretical limit our setup lies 5.9 µm resolution. In vivo MHz-OCT imaging human retina performed image quality compared to previous results acquired 70 range, as well existing...

Two-photon excitation fluorescence (TPEF) microscopy is a powerful technique for sensitive tissue imaging at depths of up to 1000 micrometers.However, due the shallow penetration, in vivo internal organs patients beam delivery by an endoscope crucial.Until today, this hindered linear and non-linear pulse broadening femtosecond pulses optical fibers endoscopes.Here we present endoscope-ready, fiber-based TPEF microscope, using nanosecond low repetition rates instead pulses.These lack most...

Two-photon-excited fluorescence lifetime imaging microscopy (FLIM) is a chemically specific 3-D sensing modality providing valuable information about the microstructure, composition and function of sample. However, more widespread application this technique hindered by need for sophisticated ultra-short pulse laser source speed limitations current FLIM detection systems. To overcome these limitations, we combined robust sub-nanosecond fiber as excitation with high analog bandwidth detection....

High-resolution frequency domain optical coherence tomography (OCT) stands out amongst a range of novel dermatologic imaging technologies, with its good detection sensitivity around -100 dB, high measurement speeds allowing real-time image acquisition and ability to acquire definition cross-sectional 3D tomograms regions greater than 1 cm2, providing tissue information comparable conventional histopathology without the need for any contrast agents. Typical axial transverse resolutions...

We report on a multi-color fiber laser based four-wave mixing (FWM) and stimulated Raman scattering (SRS), delivering rapidly wavelength switchable narrowband output at 1064, 1122, 1186 nm. High-power pulses from nanosecond pulsed master oscillator power amplifier 1064 nm are combined with 1122 of seed light for amplification the first Stokes order in standard single-mode fiber. With increasing power, we observe spectral component nm, without any additional or resonator this wavelength....

To demonstrate papillary imaging of eyes with optic disc pits (ODP) or pit associated maculopathy (ODP-M) ultrahigh-speed swept-source optical coherence tomography (SS-OCT) at 1.68 million A-scans/s. generate 3D-renderings the area 3D volume-reconstructions ODP and highly resolved en face images from a single densely-sampled megahertz-OCT (MHz-OCT) dataset for investigation ODP-characteristics.A MHz-prototype SS-MHz-OCT system 1050 nm based on Fourier-domain mode-locked laser was employed to...

Raman scattering, an inelastic scattering mechanism, provides information about molecular excitation energies and can be used to identify chemical compounds. Albeit being a powerful analysis tool, especially for label-free biomedical imaging with contrast, it suffers from inherently low signal levels. This practical limitation overcome by nonlinear enhancement techniques like stimulated (SRS). In SRS, additional light source stimulates the process. lead orders of magnitude increase in levels...

Stimulated Raman scattering (SRS) microscopy for biomedical analysis can provide a molecular localization map to infer pathological tissue changes. Compared spontaneous Raman, SRS achieves much faster imaging speeds at reduced spectral coverage. By targeting features in the information dense fingerprint region, allows fast and reliable imaging. We present time-encoded (TICO) of unstained head-and-neck biopsies region with contrast. combine Fourier-domain mode-locked (FDML) laser master...

We present a new design of Fourier Domain Mode Locked laser (FDML laser), which provides record in sweep range at ~1um center wavelength: At the fundamental rate 2x417 kHz we reach 143nm bandwidth and 120nm with 4x buffering 1.67MHz rate. The latter configuration our system is characterized: FWHM point spread function (PSF) mirror 5.6um (in tissue). Human vivo retinal imaging performed MHz showing more details vascular structures. Here could measure an axial resolution 6.0um by determining...

In order to realize fast OCT-systems with adjustable line rate, we investigate averaging of image data from an FDML based MHz-OCT-system. The rate can be reduced in software and traded for increased system sensitivity quality. We compare coherent incoherent effectively scale down the speed a 3.2 MHz OCT around 100 kHz postprocessing. demonstrate that is possible systems without special interferometer designs or digital phase stabilisation. show images human finger knuckle joint vivo very...

A system is presented that uses a fiber based Master Oscillator Power Amplifier (MOPA) with nanosecond-range pulses for two-photon excitation fluorescence (TPEF) imaging. The robust laser in the extended near infrared on an actively modulated electro-optical modulator (EOM), enabling free synchronization of to any other light source or detection unit. Pulses freely programmable duration between 0.4 and 10 ns are generated then amplified up kilowatts peak power ytterbium doped amplifiers...

Two-photon excited fluorescence (TPEF) microscopy and lifetime imaging (FLIM) are powerful techniques in bio-molecular science. The need for elaborate light sources TPEF speed limitations FLIM, however, hinder an even wider application. We present a way to overcome this by combining robust inexpensive fiber laser nonlinear excitation with fast analog digitization method rapid FLIM imaging. applied sub nanosecond pulsed source is synchronized high bandwidth signal detection single shot TPEF-...

Multi-photon microscopy is a powerful tool in biomolecular research.Less complex and more cost effective excitation light sources will make this technique accessible to broader community.Semiconductor diode seeded fiber lasers have proven be especially robust, low easy use.However, their wavelength tuning range often limited, so only limited number of fluorophores can accessed.Therefore, different approaches been proposed extend the spectral coverage these lasers.Recently, we showed that...

We present an entirely fiber based laser source for non-linear imaging with a novel approach multi-color excitation. The high power output of actively modulated and amplified picosecond at 1064 nm is shifted to longer wavelengths by combination four-wave mixing stimulated Raman scattering. By combining different types lengths, we control the wavelength conversion in delivery itself can switch between nm, 1122 1186 on-the-fly tuning pump amplifier modulate seed diodes. This promising way...

Over the last 20 years, optical coherence tomography (OCT) has become a valuable diagnostic tool in ophthalmology with several 10,000 devices sold today. Other applications, like intravascular OCT cardiology and gastro-intestinal imaging will follow. provides 3-dimensional image data microscopic resolution of biological tissue vivo. In most off-line processing acquired OCT-data is sufficient. However, for applications aided surgical microscopes, functional after stimulus, or interactive...

We present a new concept for performing stimulated Raman spectroscopy and microscopy by employing rapidly wavelength swept Fourier Domain Mode locked (FDML) lasers [1]. FDML are known fastest imaging in swept-source optical coherence tomography [2, 3]. employ this continuous repetitive sweep to generate broadband, high resolution spectra with new, time-encoded (TICO) [4]. This allows encoding detecting the gain on laser intensity directly time. Therefore we use actively modulated pump...

A fast all fiber based setup for stimulated Raman spectroscopy with a rapidly wavelength swept cw-laser is presented. It enables flexible acquisition of broadband (750 cm−1 to 3150 cm−1) spectra high resolution (0.5 cm−1).

In vivo access to molecular information of retinal tissue is considered play a critical role in enabling early diagnosis ophthalmic and neurodegenerative diseases. The current gold standard retina imaging, optical coherence tomography angiography provides only the morphology blood perfusion, missing full spectrum information. Raman spectroscopy addresses this gap while keeping investigation non-invasive label-free. Although previous studies have demonstrated huge diagnostic potential...

A system is presented that uses a fiber based Master Oscillator Power Amplifier (MOPA) with nanosecond-range pulses for two-photon excitation fluorescence (TPEF) imaging. The robust laser in the extended near infrared on an actively modulated electro-optical modulator (EOM), enabling free synchronization of to any other light source or detection unit. Pulses freely programmable duration between 0.4 and 10 ns are generated then amplified up kilowatts peak power ytterbium doped amplifiers...

We present a new concept for performing stimulated Raman spectroscopy and microscopy by employing rapidly wavelength swept Fourier Domain Mode locked (FDML) lasers [1]. FDML are known fastest imaging in swept-source optical coherence tomography [2, 3]. employ this continuous repetitive sweep to generate broadband, high resolution spectra with new, time-encoded (TICO) [4]. This allows encoding detecting the gain on laser intensity directly time. Therefore we use actively modulated pump...

A fast all fiber based setup for stimulated Raman microscopy on a rapidly wavelength swept cw-laser is presented. The applied Fourier domain mode locked (FDML) laser ring laser, providing continuously changing output over time. This source allows us to change the and, thereby energy difference with respect single color pump laser. master oscillator power amplifier amplified diode and shifter. By controlled variation of relative timing between probe an arbitrary waveform generator, signals...