California Code, Government Code - GOV § 3307

(a) No public safety officer shall be compelled to submit to alie detector test against his or her will. No disciplinary action or other recrimination shall be taken against a public safety officer refusing to submit to alie detector test, nor shall any comment be entered anywhere in the investigator's notes or anywhere else that the public safety officer refused to take, or did not take, a lie detector test, nor shall any testimony or evidence be admissible at a subsequent hearing, trial, or proceeding, judicial or administrative, to the effect that the public safety officer refused to take, or was subjected to, a lie detector test.

(b) For the purpose of this section, “lie detector” means a polygraph, deceptograph, voice stress analyzer, psychological stress evaluator, or any other similar device, whether mechanical or electrical, that is used, or the results of which are used, for the purpose of rendering a diagnostic opinion regarding the honesty or dishonesty of an individual.