Vijnana Bhairava Tantra
अनागतायां निद्रायां प्रणष्टे बाह्यगोचरे । सावस्था मनसा गम्या परा देवी प्रकाशते ॥ ७५ ॥
By entering that state preceding sleep, where the awareness of the outer world has faded, (the mind is absorbed in the threshold state) which the supreme goddess illumines.
english translation