Durgadas explains the various types of Samadhis as per the traditional Yogic view. 

 The Expressions of Samadhi: 

A Traditional Yogic Understanding of Samadhi

(c) Ved Kovid, Durgadas / Arogya Ayurvedic Health Ltd.
All Rights Reserved.

By Ved Kovid, Durgadas 

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Samadhi is the highest limb in Yoga and represents the state of Yogic absorption or trance, where all faculties of the mind or intellect (dhi) become equalised (sama) and hence its functions become absorbed, as it were, in one thing alone. It is the state of superconsciousness, however it has several levels.

Many people today talk about Samadhi or Yogic trance and absorption / immersion in an ideal, however many fail to realise that there are actually several forms of samadhis, both higher and lower. One can be in a samadhi in the regions of ignorance below the Muladhara chakra, or the consciousness of the Earth or those from the Earth up to the Sahasrara, the higher realms.

As an example, many can attain a state of the Jalaukic or higher atmospheric and watery worlds, known as the Bhuvar-Loka sphere just above this earth, where there are traces of higher light-filled mists and angelic beings. There are also semi-divine beings also.

Above the Jalaukic or water worlds above this earth are the spheres of the Swargas or heavenly abodes, the regions of light (swar) or Swar-Loka systems which relate to the cosmic element of Tejas or light and also fire. This is commonly confused by many as a "spiritual samadhi" state also when they attain it, but is again simply that of a higher level not even beyond the elements yet.

Several intellectual samadhis exist of the various levels of the mind also, such as bauddhic (intellectual) and manasic (emotional) levels, as also ahamkaric (egoistic) levels and the various sub-levels of these. For example, we can often imbibe various vasanas or impressions on a day to day level and have them imprinted upon our chitta, our mindstuff which records them and can resurface again. Other times we can become mentally engrossed in various states or samadhis - for example, watching TV, debating, reading a book, teaching, driving or eating. We are engrossed in our own worlds or lower states of samadhi, which sometimes, we can confuse as being spiritual states of consciousness or higher states of awareness.

As another example, those taking alcohol, drugs or performing pranayama or breath-control techniques can alter the physical mind and be in a temporal state of various "samadhis" that again may not be of a physical, so much as a psychological and also physical nature. Some breathing techniques such as bhastrika for example can cause us to become light-headed, or when Vata, the wind humor is high in our bodies, we may feel spaced out, detached or aloof from the world, which many neophytes confuse as being again a heightened spiritual state of being "one with all" or a spiritual samadhi, when it is simply a temporal mental disassociation with one's immediate surroundings (not even the state of entering into the astral plane, let alone the causal, let alone shaking off all five sheaths and three bodies themselves!).

There are actually four levels of Higher or Spiritual Samadhis that one needs to progress through, which are Saguna Samadhis or states where there are traces of qualities or gunas, yet even these states below are those which are attain not by one and all but by very advanced Yogis, born with previous samskaras mic impressions of previous lives of Yoga practise and good qualities as also much intense practise in this life as also very advanced, powerful and higher Gurus and much devotion.

These Saguna Samadhis are al;so known as Savikalpa Samadhis, as they are with or contain feelings or imaginations (vikalpa): 

Stage I:

The first is the tamasic samadhi, the stage of voidness (shunya) in the mind. This is the region of the akasha mahabhuta which many Yogis confuse for being the highest state, but it is not. It is simply the realisation of the akasha-tattva from the human state of mind and consciousness of which, being physical, the human state perceives anything apart from the ordinary as being (foolishly) the highest state of awareness alone! This is also the level of the cosmic Prana or life-force.

Stage II:

The second is the rajasic samadhi, the stage of the ahamkara-tattva, the ego where there is creative power. The Vaishnava Lokas and other higher causal realms exists here, as also the creative light (higher tejas), which some also confuse as the light of Brahman. Again in this state, some confuse the creative-power and light they see as being the supreme Brahman itself, although a sense of self-accomplishment is felt (due to the cosmic ahamkara-tattva) at the primal creative level. This is also the level of the cosmic Tejas or radiance which again, many confuse as the Paramjyothi, the Supreme Light.

Stage III:

The third stage is that of the sattvic samadhi, the stage of the mahat-tattva.  In this stage, one perceives the creative power of the cosmic intellect, the purified mind itself and beholds the primal Prakriti, the unmanifested nature itself, which it mistakes for Brahman. In this state, one beholds all wonders of creation, since it is the state of the cosmic buddhi tattva or mahat and as such, many reaching this state and beholding all things through the eye of the cosmic intellect, think they have attained the highest abode, but have attained the state of the cosmic mind-intellect, also known as Soma and also Ojas, for it upholds the cosmic as vitality or vital substance as the cosmic primal mind.

Stage IV:
This is the stage of the mahasattvic samadhi or greater sattvic samadhi, where one perceives the Prakriti or primal nature itself and confuses it for the Supreme or Brahman or Purusha, the primal cosmic personality or highest state. In this region, as primal nature, one perceives the reality behind the Mahat tattva of creation and beholds some sense of individuality, due to the separation and yet connection between the Prakriti and the Brahman. As unmanifested primal nature, at this level, it is again easy to see how some, beholing the mahasattvic or greater sattvic state in samadhi confuses it for the greatest.

Highest:

The final and highest stage is that of the Nirguna Samadhi or the Nirvikalpa Samadhi wherein there are no qualities or imaginations whatsoever and one merges into the highest state beyond all forms, appearances, desires and even beyond bliss. There are no thoughts or imaginations in this state; the mind is completely silenced beyond attributes or gunas.

It is not void, but it is the highest light through which one has attained and merges with and remains. There is no sense of ego or accomplishment, nor is there any sense of individuality at all (meaning there is nothing to "perceive" as such, as perception itself would infer a separate identity) and one has no desire no beholds any wonders of the lower worlds of creation, nor sees them, merging into the primal consciousness behind all - behind even the paramanus (subatomic particles) that make up the anus or atoms, the building-blocks of creation! 

In traditional Shaivite Yoga, there are also seven parachakras or spheres above the Sahasrara Padma or crown-chakra or Satya-Loka, the highest abode. In Vaishnavism, these are described as their Paralokas or transcendental realms which one requires a kind of transcendental causal body to enter, although they attribute various physical traits and qualities (gunas) to these abodes. Still, they represent various stages above the Satya-Loka or Sahasrara of which they see as the realm of simply Brahma, the creator.

As noted however, these are the highest levels that one experiences in higher samadhis of advanced Yoga alone, what to speak of the mind-born creations and intellectual samadhis that one has, in the modes of the physical mind alone and of mudha (deluded), kshipta (wondering), vikshipta (scattered or projectory) and so on. These are also powers and functions of the mind itself, which have to be overcome, not simply mistaken for being spiritual realisations and samadhis as many do today, simply as they are not aware of the various obstacles and levels in Yoga itself that have to be overcome.

For example, one can easily fall into Unmada Samadhi or insanity samadhi classifications, according to the variations of rajas and tamas in their minds in Ayurveda which bring this on, and lead a person to be in a kind of mudha or deluded samadhi or state of absoprtion in their own little worlds!  Those having Bhutunmada that is, psychic possession which leads to insanity, are also in states of lower samadhis also, for they are engrossed or absorbed again in the vikalpas or imaginations of their mind.

Unless the mind itself is completely sattvic or pure and purified (shuddhi) as also ekagra or single-pointed and nirudha, where all functions of the mind have complete ceased or no longer function (nir), there is no chance of attaining the true higher samadhis and accessing them. This requires Dharana in order to develop however before going in for dhyana or meditation, or one suffers the same delusions there also.

Patanjali in his Yoga Sutras speaks about samyama (yogic concentration), that is, the culmination of dharana (concentration), dhyana (meditation) and samadhi on various concepts and the various kinds of supernatural powers and realms one can enter and attain as a result. These, these also bring about simply only lower states of samadhi according to true Yoga, not that of the Self.

This is why in the Upanishads, the oldest texts dealing with the Self and Yoga in-depth, do not speak about samyama and concentrate on these supernatural aspects for they do not aim at the supreme samadhi or the Nirguna Samadhi, the highest beyond all other states and qualities altogether. They hence speak simply about the formless, attributeless Brahman and how to attain that state, dismissing or ignoring, as it were, the other (lesser) levels, lest ignorant people fall into deluded levels.

References:

Patanjali Yoga Sutras

Durgadas (Rodney) Lingham, Vaidik Para-Yoga Vijnana: Lulu Publications, 2012

Swami Yogeshwaranand,  Atma Vijnana: Yoga Niketan Trust, New Delhi, 2007

Dr. David Frawley: Lecture Notes on Yoga and Ayurveda