Preliminary research with non-human animals suggests that LLLT (i.e., ultra low doses of transcranial infrared light) can enhance the retention of fear extinction learning by up regulating neuronal metabolic activity when applied to the ventromedial prefrontal cortex (vmPFC). Furthermore, evidence from a previous uncontrolled trial with humans suggests that LLLT (outside the context of extinction training) can lead to a significant decrease in symptoms of depression and anxiety when applied to the right and left dorsolateral prefrontal cortices (dlPFC). The first aim of this study is to test whether LLLT can boost fear reduction after extinction training in humans. A second aim of this study is to investigate the efficacy of LLLT as a stand-alone anxiolytic intervention in a randomized controlled trial.