zero-mode waveguide is an

optical waveguide An optical waveguide is a physical structure that guides electromagnetic waves in the optical spectrum. Common types of optical waveguides include optical fiber waveguides, transparent dielectric waveguides made of plastic and glass, liquid light g ...

that guides light energy into a volume that is small in all dimensions compared to the

wavelength In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tro ...

of the light. Zero-mode waveguides have been developed for rapid parallel sensing of

zeptolitre The litre (international spelling) or liter (American English spelling) (SI symbols L and l, other symbol used: ℓ) is a metric unit of volume. It is equal to 1 cubic decimetre (dm3), 1000 cubic centimetres (cm3) or 0.001 cubic metre (m3). ...

sample volumes, as applied to gene sequencing, by

Pacific Biosciences Pacific Biosciences of California, Inc. (aka PacBio) is an American biotechnology company founded in 2004 that develops and manufactures systems for gene sequencing and some novel real time biological observation. PacBio describes its platfor ...

(previously named Nanofluidics, Inc.) A waveguide operated at frequencies lower than its

cutoff frequency In physics and electrical engineering, a cutoff frequency, corner frequency, or break frequency is a boundary in a system's frequency response at which energy flowing through the system begins to be reduced ( attenuated or reflected) rather than ...

(wavelengths longer than its

cutoff wavelength In physics and electrical engineering, a cutoff frequency, corner frequency, or break frequency is a boundary in a system's frequency response at which energy flowing through the system begins to be reduced ( attenuated or reflected) rather than ...

) and used as a precision attenuator is also known as a "waveguide below-cutoff attenuator." The zero-mode waveguide is made possible by creating circular or rectangular nanoapertures using

focused ion beam Focused ion beam, also known as FIB, is a technique used particularly in the semiconductor industry, materials science and increasingly in the biological field for site-specific analysis, deposition, and ablation of materials. A FIB setup is a s ...

on an aluminium layer. The zero-mode waveguide can also enhance fluorescence signals due to surface plasmon generated at metal-dielectric interfaces. Due to surface plasmon generation field is localized and enhanced as well as it changes the LDOS inside the cavity which leads to increase in Purcell Factor of analyte molecules inside the zero-mode waveguide The zero-mode waveguide is very useful for Ultraviolet Auto-fluorescence spectroscopy on tryptophan-carrying proteins like beta-galactosidase with further modification of the zero-mode waveguide with a conical reflector its possible to study the dynamic process of smaller proteins like streptavidin with 24 tryptophan. , The modified zero-mode waveguide with a conical reflector can be further optimized to enhance the Signal-to-noise ratio and reach the ultimate sensitivity of single tryptophan proteins like TNase.

References

Biophysics Physical optics {{biophysics-stub

See also

References