The phrase "popularity spread" is correct and usable in written English.
You can use this phrase when referring to the expansion of the popularity of something. For example, you could say "The popularity of roller skating spread across the city in the 1980s."
The game became popular with leftwing intellectuals and on college campuses, and that popularity spread throughout the next three decades; it eventually caught on with a community of Quakers in Atlantic City, who customised it with the names of local neighbourhoods, and from there it found its way to Charles Darrow.
And her popularity spread far beyond opera audiences.
Many visitors saw velocipedes on the streets; popularity spread; and the number of makers multiplied.
The campaign's popularity spread by tapping into widening discontent over the state of the country.
His popularity spread, and he began traveling to Kyōto to perform there as well.
His popularity spread rapidly; churches and shrines were constructed in his honour in England, Sweden, and Rome.
Sales of Pope Francis-related merchandise is booming as the pontiff's popularity spreads across the globe.
But even as its popularity spreads to new markets, the global supply and quality of oud is starting to fade.
In the years following those embryonic days, the movement surged in popularity, spreading across Europe, and in 1913 it was decided that every year, on 8 March, women would express solidarity in their campaign for equality.
When Alabama Shakes' popularity spreads beyond the cognoscenti to the festival crowds, there will be many a drunken arm slung around many a drunken shoulder, bawling along with "Hang Loose".
Boot camps, group workouts with military flavor and fervor, are by no means new, but they have been growing in popularity, spreading from the city's parks — Central, Battery, Washington Square and Prospect, among others — to the suburbs.
