Two-photon microscope

Definition

A two-photon microscope is an advanced fluorescence imaging technique that allows visualization of living tissues up to a depth of about one millimeter. It uses two photons of lower energy instead of one photon of higher energy to excite fluorophores, minimizing photodamage and allowing deeper tissue penetration.

5 Must Know Facts For Your Next Test

1. Two-photon microscopy utilizes near-infrared light for deeper tissue penetration and reduced scattering compared to single-photon microscopy.
2. This technique minimizes photodamage and photobleaching, making it ideal for long-term imaging of live cells.
3. Two-photon excitation occurs only at the focal point, leading to inherent optical sectioning and high-resolution images.
4. Common applications include in vivo imaging of neural activity, blood flow, and other dynamic processes in living organisms.
5. Two-photon microscopes require a mode-locked laser, which produces short pulses necessary for simultaneous absorption of two photons.

Review Questions

• What type of light does a two-photon microscope use to achieve deeper tissue penetration?
• How does two-photon microscopy minimize photodamage compared to single-photon microscopy?
• Why is two-photon excitation beneficial for optical sectioning?

Related terms

Fluorescence Microscopy: A technique that uses fluorescence instead of or in addition to reflection and absorption to study properties of organic or inorganic substances.

Confocal Microscopy: An optical imaging technique that increases optical resolution and contrast by using a spatial pinhole to block out-of-focus light.

Multiphoton Excitation: A process where multiple photons are absorbed simultaneously by a molecule, typically used in advanced microscopy techniques like two-photon microscopy.