Probing the fluctuating vacuum According to quantum mechanics, a is not empty space. A consequence of uncertainly principle that particles or energy can come into existence for fleeting moment. Such fluctuations are known exist, but evidence them has been indirect. Riek et al. present an ultrafast optical based technique probes fluctuation electromagnetic radiation directly. Science , this issue p. 420

A passively phase-locked laser source based on compact femtosecond Er:fiber technology is introduced. The carrier-envelope offset frequency set to zero via difference generation between a soliton at wavelength of 2 μm and dispersive wave 860 nm generated in the same highly nonlinear fiber. This process results broadband output centered 1.55 μm. Subsequently, 40 MHz pulse train seeds second amplifier, which boosts energy up 8 nJ duration 125 fs. Excellent phase stability demonstrated f-to-2f...

Direct detection of vacuum fluctuations and analysis subcycle quantum properties the electric field are explored by a paraxial theory ultrafast electro-optic sampling. The feasibility such experiments is demonstrated realistic calculations adopting thin ZnTe crystal stable few-femtosecond laser pulses. We show that nonlinear mixing short near-infrared probe pulse with multiterahertz leads to an increase signal variance respect shot noise level. contribution increases significantly for...

Ultrashort time-domain spectroscopy and field-resolved of molecular fingerprints are gold standards for detecting samples’ constituents internal dynamics. However, they hindered by the Nyquist criterion, leading to prolonged data acquisition, processing times, sizable volumes. In this work, we present first experimental demonstration compressed sensing on fingerprinting employing random scanning. Our measurements enable pinpointing primary absorption peaks atmospheric water vapor in response...

Optical frequency combs based on erbium-doped fiber lasers are attractive tools in precision metrology due to their inherent compactness and stability.Here we study a femtosecond Er:fiber comb that passively eliminates the carrierenvelope phase slip by difference generation.Quantum statistics inside all-fiber soliton oscillator governs its free-running performance.Active stabilization of repetition rate supports subhertz optical linewidth does not necessitate additional intracavity...

Ultrabroadband electro-optic sampling is presented as an extremely sensitive technique to detect electric field amplitudes in free space. The temporal resolution provided by few-femtosecond laser pulses results a bandwidth exceeding 100 THz, potentially covering the entire infrared spectral range. A pedagogic introduction operational principle of method given along lines classical coherent input and zincblende-type sensor. We then show that even bare vacuum fluctuations quantum ground state...

A highly stable setup for stimulated Raman scattering (SRS) microscopy is presented. It based on a two-branch femtosecond Er:fiber laser operating at 40 MHz repetition rate. One of the outputs directly modulated Nyquist frequency with an integrated electro-optic modulator (EOM). This compact source combines jitter-free pulse synchronization broad tunability and allows shot-noise limited SRS detection. The performance microscope illustrated measurements samples from material science cell biology.

Stimulated Raman scattering (SRS) microscopy is an important non-linear optical technique for the investigation of unlabeled samples. The SRS signal manifests itself as a small intensity exchange between laser pulses involved in coherent excitation modes. Usually, high-frequency modulation applied one pulse train, and then detected on other train via lock-in amplification. While allowing shot-noise limited detection sensitivity, detection, which corresponds to filtering frequency domain, not...

A phase-locked terahertz transient is exploited as an ultrafast phase gate for femtosecond optical pulses. We directly map out the group delay dispersion of a low-power near-infrared pulse by measuring electro-optically induced polarization rotation function wavelength. Our experiment covers spectral window from 1.0 to 1.4 μm and reaches temporal precision better than 1 fs. quantitative analysis detector response confirms that this streaking technique requires no reconstruction algorithm...

The nonlinear transformation of fluctuations by frequency broadening is found to produce strong anti-correlations in the spectral output. This effect investigated dispersive Fourier transform measurements. We exploit order cancel intensity noise a subsequent sum-frequency mixing step. principle allows for generation tunable visible pulses cascaded whilst maintaining same performance as input pulses. In addition, we demonstrate that power occurring process passive stabilization...

Abstract We explore background-free options to detect mid-infrared (MIR) electric transients. The MIR field and a near-infrared probe interact via sum- (SFG) difference-frequency generation (DFG) in an electro-optic crystal. An intuitive picture based on phasor representation rigorous numerical calculations are used for analysis. It turns out that separating photons generated either by SFG or DFG from the local oscillator spectral filtering leads signal purely proportional intensity...

Compact and broadband mid-infrared (MIR) sources are in high demand because of a wide range potential applications such as molecular sensing the fingerprint region. The generation coherent MIR radiation at arbitrary frequencies typically requires nonlinear mixing between least two input waves, which is often cumbersome to implement. We present an integrated and, therefore, adjustment-free solution combining few-femtosecond pulse compression germanosilicate optical fiber rectification. To...

We directly detect the multi-terahertz vacuum field and analyze its dependence on probed space-time volume. A scheme for sensing time derivative of enables time-domain quantum tomography with simultaneous sampling both quadratures.

We introduce a novel streaking scheme based on electro-optic detection of terahertz (THz) transients to characterize optical pulses with ultrabroad bandwidths, directly in the time domain. This principle may readily be extended towards spectral widths multiple octaves.

Quantum field theory offers the most exact description of physics microscopic interactions. The process offield quantization necessitates existence a vacuum with corresponding zero-point energy [1]. From this point view, ability to directly measure and manipulate electrodynamic quantum is an attractive prospect for experimental physics. It bound shed new light on processes governing macroscopic properties matter [2, 3] as well motivate table-top investigations fundamental constituents fields...

We describe application of a state-of-the art digital FPGA based Lock-In amplifier to measurements ultrasound propagation and attenuation at fixed frequency in low temperatures high static magnetic fields. Our implementation significantly simplifies electronics required for resolution measurements, allows record the full echo train single measurement extract changes both phase amplitude an arbitrary number echa as function external control parameter. The system is simple operation requiring...

Electro-optic sampling at center frequency and bandwidth around 70 THz allows measuring the vacuum fluctuations of electric field in free space. Distinction from detector shot noise is accomplished by modifying space-time volume probed.

Abstract Vakuum‐Fluktuationen sind eine grundlegende Konsequenz der Heisenbergschen Unschärferelation. Motiviert durch die Tatsache, dass elektrische und magnetische Feldamplituden nicht gleichzeitig verschwinden können, beschreibt Quantenelektrodynamik (QED) sie als Photonen, spontan aus dem Nichts entstehen wieder zerfallen. Die Lebensdauer dieser virtuellen Anregungen ist dabei Oszillationsperiode Strahlung im jeweiligen Frequenzbereich gegeben. Mit einer Zeitauflösung besser...

We directly detect the multi-terahertz vacuum field and analyze its dependence on probed space-time volume. A scheme for sensing time derivative of enables time-domain quantum tomography with simultaneous sampling both quadratures.

We generate few-cycle nonclassical transients by optical rectification of femtosecond pulses and subsequent index modulation in the multi-THz range. Subcycle analysis quantum statistics ultrabroadband electro-optic sampling reveals substantial squeezing below vacuum level.

We conclude that we have demonstrated an all-passive stabilization of a compact Er:fiber laser system. The phase-locked seed is reamplified to pulse energies compatible with the established variety fs-Er:fiber technology, enabling high tunability and single-cycle light pulses.