"The light experience is of course described again and again in the religious literature. After all, the most celebrated cases, (the light experience by St. Paul on the road to Damascus; a tremendous explosion of light which woke Mohammed out of sleep and which made him faint from its intensity; the experience of tremendous light which Plotinus described as having three or four times in his life)-you will find this again and again in literature. . ." pg.48 'Visionary Experience' by Aldous Huxley.
We have to look at the account of the Apostle Paul's experience of light in the New Testament book The Acts of the Apostles chapter 9, "As he journeyed he came near Damascus, and suddenly a light shone around him from heaven. Then he fell to the ground, and heard a voice saying to him, "Saul, Saul, why are you persecuting Me?" And he said, "Who are You, Lord?" Then the Lord said, "I am Jesus, whom you are persecuting. It is hard for you to kick against the goads. So he, trembling and astonished, said, "Lord, what do You want me to do?" Then the Lord said to him, "Arise and go into the city, and you will be told what you must do." In chapter 26 of Acts we also find the Apostle Paul telling King Agrippa about his Damascus road encounter with the Risen Exalted Lord Jesus Christ, "at midday, O king, along the road I saw a light from heaven, brighter than the sun, shining around me and those who journeyed with me. And when we all had fallen to the ground, I heard a voice speaking to me and saying in the Hebrew language, "Saul, Saul, why are you persecuting Me? It is hard for you to kick against the goads. So I said, "'Who are You, Lord?" And He said, 'I am Jesus, whom you are persecuting" Acts 26:13-15.
What we have recorded in the Acts is the calling of the Saul of Tarsus being called to the office of Apostle, we read in Acts 26 verse 16, "But rise and stand on your feet; for I have appeared to you for this purpose, to make you a minister and a witness both of the things which you have seen and of the things which I will yet reveal to you. . ."
When a Christian sees the light (mystical experience) it always the light of the glory of the Lord Jesus Christ. We read in Second Corinthians, 'But we all, with unveiled face beholding as in a mirror the glory of the Lord, are being transformed into the same image from glory to glory, just as by the Spirit of the Lord" 2 Corinth. 3:18.
Check out these books on the Apostle Paul's Damascus Road experience-
"The Road From Damascus: The Impact of Paul's Conversion on His Life, Thought, and Ministry" Edited by Richard N. Longenecker
"The Origin Of Paul's Gospel" by Seyoon Kim
I will close with a quote from the book, "The Origin Of Paul's Gospel" by Seyoon Kim-
"However, when the glory of God shone in the face of Christ and Christ appeared as the image of God on the Damascus road, Paul knew that the hope for their restoration in the messianic age had become a reality in Christ. In the face of Christ (2Cor. 4.6) Paul saw shining the original divine image, the lustre on the face of Adam, which was suppose to have outshoned the sun but had been lost through his fall. Since Christ in whom the divine glory was restored was none other than the crucified and risen Jesus of Nazareth, Paul also knew that the life (eternal life or immortality) which had been lost through Adam's sin, was now restored in Christ. . ." pg.262