Patent ID: 7612935

Claim:
A method for producing a third harmonic signal from a laser light of wavelength λ, comprising: irradiating said laser light on a material including a molecule having a formula D-Π-A, where D is an electron donor group, A is an electron acceptor group, and Π is a conjugated structure having π bonds that connect the D donor group to the A acceptor group, said molecule exhibiting an absorption band at a wavelength λ 0 and exhibiting a weakly absorbing region as compared to the absorption band at λ 0 at a wavelength λ 1 , such that λ 1 <λ 0 ; adjusting the wavelength λ of said laser light such that λ/2 has a value of about λ 0 and λ/3 has a value of about λ 1 , thereby generating said third harmonic signal.