Squeezed states of light enable enhanced measurement precision by reducing noise below the standard quantum limit. A key application of squeezed light is nonlinear microscopy, where state-of-the-art performance is limited by photodamage and quantum-limited noise. Such microscopes require bright, pulsed light for optimal operation, yet generating and detecting bright pulsed squeezing at high levels remains challenging. In this work, we present an efficient technique to generate high levels of bright picosecond pulsed squeezed light using a $χ^2$ optical parametric amplification process in a waveguide. We measure $-3.2~\mathrm{dB}$ of bright squeezing with optical power compatible with nonlinear microscopy, as well as $-3.6~\mathrm{dB}$ of vacuum squeezing. Corrected for losses, these squeezing levels correspond to $-15.4^{+2.7}_{-8.7}~\mathrm{dB}$ of squeezing generated in the waveguide. The measured level of bright amplitude pulsed squeezing is to our knowledge the highest reported to date, and will contribute to the broader adoption of quantum-enhanced nonlinear microscopy in biological studies.Squeezed states of light enable enhanced measurement precision by reducing noise below the standard quantum limit. A key application of squeezed light is nonlinear microscopy, where state-of-the-art performance is limited by photodamage and quantum-limited noise. Such microscopes require bright, pulsed light for optimal operation, yet generating and detecting bright pulsed squeezing at high levels remains challenging. In this work, we present an efficient technique to generate high levels of bright picosecond pulsed squeezed light using a $χ^2$ optical parametric amplification process in a waveguide. We measure $-3.2~\mathrm{dB}$ of bright squeezing with optical power compatible with nonlinear microscopy, as well as $-3.6~\mathrm{dB}$ of vacuum squeezing. Corrected for losses, these squeezing levels correspond to $-15.4^{+2.7}_{-8.7}~\mathrm{dB}$ of squeezing generated in the waveguide. The measured level of bright amplitude pulsed squeezing is to our knowledge the highest reported to date, and will contribute to the broader adoption of quantum-enhanced nonlinear microscopy in biological studies.

quant-pharXiv:2601.15565Jan 23, 20260 citations

Squeezed light improves sensitivity of microscopy technique

Eric Olaf Potma

NatureJun 9, 20212 citations

Plasmon enhanced fluorescence microscopy below quantum noise limit with reduced photobleaching effect

Partha Pratim Mondal, Russell Gilbert, Peter T. C. So

We propose a plasmon enhanced fluorescence microscopy technique below the quantum noise limit. This is achieved by exciting fluorescent molecules with photon number squeezed (PNS) light and using nanoparticles as an enhancer for overcoming the low absorption cross section. PNS light has an inherent sub-Poissonian photon distribution for which the variance Δn<⟨n⟩. PNS light has the added advantage of antibunching, which eliminates photobleaching due to higher order photon interactions. We anticipate that single molecule studies will benefit from such a radiation source.We propose a plasmon enhanced fluorescence microscopy technique below the quantum noise limit. This is achieved by exciting fluorescent molecules with photon number squeezed (PNS) light and using nanoparticles as an enhancer for overcoming the low absorption cross section. PNS light has an inherent sub-Poissonian photon distribution for which the variance Δn<⟨n⟩. PNS light has the added advantage of antibunching, which eliminates photobleaching due to higher order photon interactions. We anticipate that single molecule studies will benefit from such a radiation source.

Applied Physics LettersSep 1, 20087 citations

Sub-shot-noise microscopy with squeezed light

Mikhail I. Kolobov, Prem Kumar

Quantum limit of sensitivity in optical imaging with coherent light is set by the shot noise of photodetection.

Annual Meeting Optical Society of AmericaJan 1, 19930 citations

χ^2

optical parametric amplification process in a waveguide. We measure

-3.2~\mathrm{dB}

of bright squeezing with optical power compatible with nonlinear microscopy, as well as

-3.6~\mathrm{dB}

of vacuum squeezing. Corrected for losses, these squeezing levels correspond to

-15.4^{+2.7}_{-8.7}~\mathrm{dB}

of squeezing generated in the waveguide. The measured level of bright amplitude pulsed squeezing is to our knowledge the highest reported to date, and will contribute to the broader adoption of quantum-enhanced nonlinear microscopy in biological studies.