story identification - I'm looking for a fiction novel series about a submarine, being the USS Seawolf, finding the world in flames after a nuclear war.

The description is a mismatch as I am looking for the same series. The submarine was a Typhoon-class submarine that the US had purchased and turned into an underwater sea craft sub. The blue-green lasers were used as radar by the main ship as well as the mini-subs launched by it. There were underwater missiles. The story is not post-apocalyptic, but more a shift in global power where the US was fighting for its position. The ship was called the Sea-Wolf.

Update

I think you may have conflated two books; Stingray by Bill Keith and the Attack of the Seawolf series by Michael DiMercurio.

Stingray

Leviathan—the world's largest Typhoon-type vessel, a subcarrier
equipped with the most advanced twenty-first-century laser technology
and the ultimate weapon—a fast, agile fleet of SFV-4B Barracudas, the
undersea version of the world's hottest new fighter plane.

The ultimate undersea challenge

Fresh from bloody battle off the coast of Cuba, Leviathan rides out to
meet trouble at its source—Alexandria. There the formidable Islamic
navy and its allies gather, sailing through the Strait of Gibraltar to
block South American oil supplies and bring America to its knees.

Challenged by the Teigei, a Japanese supersub whose superior
technology matches Leviathan's, Commander T. Morgan Gray, ace Navy
pilot, must lead his intrepid men into a chilling undersea battle—one
where only their daring, skill, and courage can snatch victory from
the jaws of death and devastating final defeat.

Attack of the Seawolf

In the near future posited by this convincing techno-thriller, China
has collapsed into civil war. The U.S. nuclear sub Tampa, sent into
the Gulf of Chilhi to collect intelligence, is discovered and captured
by the communists. The Navy's newest submarine, the Seawolf, embarks
with a crack SEAL team for a rescue mission captained by Michael
Pacino, who lost his last ship in last year's Voyage of the Devilfish.
Now Pacino takes the Seawolf on a high-tech cutting-out expedition
in the best tradition of 18th-century naval warfare