Cy®5 dye is a bright, far-red-fluorescent dye with excitation ideally suited for the 633 nm or 647 nm laser lines. A significant advantage to using long wavelength dyes such as Cy®5 dye or Alexa Fluor® 647 dye over other fluorophores is the low autofluorescence of biological specimens in this region of the spectrum.
The Cy®5 fluorophore is also the basis for the lipophilic neuronal and long-term DiD cell tracing reagents, which append alkyl tails (≥12 carbons) onto the core fluorophore. 

Optolong Optics Co.,ltd is the brand owner of optolong who is a manufacturer of astronomy filters, fluorescence filters. We also offer other interference filters like UV filters, visible filters and Near inferred filters, beam splitter, anti-reflection coating and optical mirrors as a OEM service.

Located in Kunming city in China which is one of the four optics center and the coating experience of 18 years (since 1999) enable us to design and produce the filters with most sophisticated spectrum.

We are glad to declare that Optolong has been become the first and only non-replaceable brand for astronomical filters in China. Optolong brand is also known as the comparable filters with international brand by distributor client around the world.