Third harmonic generation microscopy.

Third harmonic generation microscopy is used to make dynamical images of living systems for the first time. A 100 fs excitation pulse at 1.2 aem results in a 400 nm signal which is generated directly within the specimen. Chara plant rhizoids have been imaged, showing dynamic plant activity, and non-fading image characteristics even with continuous viewing, indicating prolonged viability under these THG-imaging conditions.