What is a Longpass filter?

Longpass filters are optical filters that reflect short wavelengths while transmitting, or passing, long wavelengths. Conversely, Shortpass filters transmit short wavelengths but reflect long ones.

What is an Edgepass filter?

Edgepass filters are called short-pass or long-pass according to whether they transmit below or above their transition wavelength. Our Short-wave and Long-wave Pass Filters exhibit a sharp transition from a spectral region of attenuation to one of transmission. They may also be used as heat or UV filters.

How do Longpass filters work?

Longpass. A longpass (LP) Filter is an optical interference or coloured glass filter that attenuates shorter wavelengths and transmits (passes) longer wavelengths over the active range of the target spectrum (ultraviolet, visible, or infrared).

What is spectral filter?

Spectral filters are used to selectively transmit light according to its wavelength. Spectral filters are not to be mistaken with color filters, which can be differentiated by an associated schott glass number. There are several types of spectral filters. Examples include light filters and dichroic filters.

What is a Shortpass filter?

Shortpass Filters, also known as Shortpass Edge Filters, are used to transmit wavelengths shorter than the cut-off wavelength of the filter. Shortpass Filters are commonly use in life science applications including fluorescence microscopy or for integration into a variety of instrumentation.

What is cut on wavelength?

Cut-on wavelength describes an optical filter edge transition where transmission increases sharply over an increasing wavelength range, such as seen with a longpass filter. Conversely, cut-off wavelength describes an edge transition that decreases over a wavelength range, as seen with a shortpass filter.

How does an interference filter work?

An interference filter or dichroic filter is an optical filter that reflects one or more spectral bands or lines and transmits others, while maintaining a nearly zero coefficient of absorption for all wavelengths of interest.

How does notch filter work?

A Notch Filter is also known as a Band Stop filter or Band Reject Filter. These filters reject/attenuate signals in a specific frequency band called the stop band frequency range and pass the signals above and below this band. The lower the insertion loss outside the stop band the better.

What are the two main differences between short pass filters and long pass filters?

Long pass and short pass filters are two distinct types of specialized optical filters. Long pass filters transmit electromagnetic radiation with long wavelengths while blocking shorter wavelengths. Short pass filters do the opposite: they pass short wavelengths and block longer ones.

What are the differences between absorption and interference filters?

Absorption Filters. Explore how gelatin and glass absorption filters are used to pass a specific band of wavelengths. Interference Filters – These filters differ from absorption filters in the fact that they reflect and destructively interfere with unwanted wavelengths as opposed to absorbing them.

Why choose thorthorlabs’ filters?

Thorlabs’ longpass and shortpass filters are very useful for isolating regions of a spectrum. These edgepass filters feature durable dielectric coatings that withstand the normal cleaning and handling necessary when using any high-quality optical component.

What colored glass filters does Thorlabs offer?

Click on for a plot and downloadable data. Thorlabs offers two filter kits that bundle our most popular longpass and bandpass colored glass filters. The FGK01 Colored Glass Filter Kit contains three filters from our bandpass family and seven from our longpass family.

What are longpass colored glass filters made of?

These longpass colored glass filters are manufactured from different colors of Schott ® glass and are intended for use in a wide variety of applications. The filters are available in both round and square varieties. The Ø25 mm round filters will fit into our manual or motorized filter wheels; alternatively, they can be mounted in a lens tube.

How can the central wavelength of the bandpass filter be tuned?

The central wavelength of the bandpass filter can be tuned slightly (~1 nm over the operating range of the filter) by changing the temperature of the filter. This is primarily due to the slight thermal expansion or contraction of the layers.