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You can get the citta into samadhi with what the buddha calls āloka·saññaṃ which is sanna of light. The result of this samadhi is the knowledge of karma and before that, it energizes you.
And what is the development of concentration that, when developed & pursued, leads to the attainment of knowledge & vision? There is the case where a monk attends to the perception of light and is resolved on the perception of daytime [at any hour of the day]. Day [for him] is the same as night, night is the same as day. By means of an awareness open & unhampered, he develops a brightened mind. This is the development of concentration that, when developed & pursued, leads to the attainment of knowledge & vision.
http://www.buddha-vacana.org/sutta/anguttara/04/an04-041.html
Unfortunately, this samadhi is the least detailed of the 4 samadhis. Some puthujjanas claim it is just perceiving light, some say the light means the light of the jhanas (because they claim that the mind is luminous in jhanas), some say it is a kasina and some say it is light of wisdom...
Do not forget to perceive the origination, establishment and cessation in order to become an arhant.
For more info you can read
for the energy, section ''The 8 ways of overcoming drowsiness'' http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/4.11-Pacala-S-a7.58-piya.pdf
for the karma http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/24.1-Samadhi-Bhavana-S-a4.41-piya.pdf